Sql 在列中重复值_Sql_Oracle_Oracle11g

Sql 在列中重复值

sql oracle oracle11g

Sql 在列中重复值,sql,oracle,oracle11g,Sql,Oracle,Oracle11g,我在一列中有以下值，这些值用逗号分隔 BHOP23,BHOP23,BHOP24 我想知道值是否在列中重复如何执行此操作？Oracle安装程序： CREATE TABLE your_table ( your_list_column ) AS SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at he

我在一列中有以下值，这些值用逗号分隔

BHOP23,BHOP23,BHOP24

我想知道值是否在列中重复

如何执行此操作？

Oracle安装程序：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

要获取具有重复值的列表，可以在正则表达式中使用反向引用：

SELECT *
FROM   your_table
WHERE  REGEXP_LIKE( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,' )

SELECT your_list_column,
       REGEXP_SUBSTR( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,', 1, 1, NULL, 1 )
         AS duplicate_value
FROM   your_table
WHERE  REGEXP_LIKE( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,' )

输出：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

要获取第一个重复值，可以提取上述正则表达式的第一个子组：

SELECT *
FROM   your_table
WHERE  REGEXP_LIKE( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,' )

SELECT your_list_column,
       REGEXP_SUBSTR( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,', 1, 1, NULL, 1 )
         AS duplicate_value
FROM   your_table
WHERE  REGEXP_LIKE( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,' )

输出：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

要获得唯一值，请使用（但使用用户定义的类型，而不是预定义的

VARRAY

）：

输出：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

Oracle安装程序：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

要获取具有重复值的列表，可以在正则表达式中使用反向引用：

SELECT *
FROM   your_table
WHERE  REGEXP_LIKE( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,' )

SELECT your_list_column,
       REGEXP_SUBSTR( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,', 1, 1, NULL, 1 )
         AS duplicate_value
FROM   your_table
WHERE  REGEXP_LIKE( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,' )

输出：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

要获取第一个重复值，可以提取上述正则表达式的第一个子组：

SELECT *
FROM   your_table
WHERE  REGEXP_LIKE( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,' )

SELECT your_list_column,
       REGEXP_SUBSTR( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,', 1, 1, NULL, 1 )
         AS duplicate_value
FROM   your_table
WHERE  REGEXP_LIKE( ',' || your_list_column || ',', ',([^,]+),(.+,)?\1,' )

输出：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

要获得唯一值，请使用（但使用用户定义的类型，而不是预定义的

VARRAY

）：

输出：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

仅依赖简单字符串函数（

SUBSTR

、

INSTR

和

LENGTH

）从字符串列表中删除重复项的PL/SQL函数：

Oracle 11g R2架构设置：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

仅依赖简单字符串函数（

SUBSTR

、

INSTR

和

LENGTH

）从字符串列表中删除重复项的PL/SQL函数：

Oracle 11g R2架构设置：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

：

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL;          -- no duplicates

YOUR_LIST_COLUMN
----------------
a,a,b,c,d
a,b,a,c,d
a,b,c,d,a
a,b,b,c,d
a,b,c,b,d
a,b,c,d,b
a,b,c,d,d
a,b,a,c,b

YOUR_LIST_COLUMN DUPLICATE VALUE
---------------- ---------------
a,a,b,c,d        a
a,b,a,c,d        a
a,b,c,d,a        a
a,b,b,c,d        b
a,b,c,b,d        b
a,b,c,d,b        b
a,b,c,d,d        d
a,b,a,c,b        a

YOUR_LIST_COLUMN UNIQUE_LIST
---------------- ---------------
a,a,b,c,d        a,b,c,d
a,b,a,c,d        a,b,c,d
a,b,c,d,a        a,b,c,d
a,b,b,c,d        a,b,c,d
a,b,c,b,d        a,b,c,d
a,b,c,d,b        a,b,c,d
a,b,c,d,d        a,b,c,d
a,b,a,c,b        a,b,c
a,b,c,d,e        a,b,c,d,e

CREATE TABLE your_table ( your_list_column ) AS
  SELECT 'a,a,b,c,d' FROM DUAL UNION ALL -- duplicates both at head
  SELECT 'a,b,a,c,d' FROM DUAL UNION ALL -- duplicates at head and middle
  SELECT 'a,b,c,d,a' FROM DUAL UNION ALL -- duplicates at head and tail
  SELECT 'a,b,b,c,d' FROM DUAL UNION ALL -- duplicates at middle and next item
  SELECT 'a,b,c,b,d' FROM DUAL UNION ALL -- duplicates at middle and middle
  SELECT 'a,b,c,d,b' FROM DUAL UNION ALL -- duplicates at middle and tail
  SELECT 'a,b,c,d,d' FROM DUAL UNION ALL -- duplicates both at tail
  SELECT 'a,b,a,c,b' FROM DUAL UNION ALL -- two pairs of duplicates
  SELECT 'a,b,c,d,e' FROM DUAL           -- no duplicates
/

CREATE OR REPLACE FUNCTION remove_Duplicates_From_List(
  i_str    IN  VARCHAR2,
  i_delim  IN  VARCHAR2 DEFAULT ','
) RETURN VARCHAR2 DETERMINISTIC
AS
  p_result       VARCHAR2(4000) := i_delim;
  p_temp         VARCHAR2(4000);
  p_start        NUMBER(5) := 1;
  p_end          NUMBER(5);
  c_len CONSTANT NUMBER(5) := LENGTH( i_str );
  c_ld  CONSTANT NUMBER(5) := LENGTH( i_delim );
BEGIN
  IF c_len > 0 THEN
    p_end := INSTR( i_str, i_delim, p_start );
    WHILE p_end > 0 LOOP
      p_temp := SUBSTR( i_str, p_start, p_end + c_ld - p_start );
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
      p_start := p_end + c_ld;
      p_end := INSTR( i_str, i_delim, p_start );
    END LOOP;
    IF p_start <= c_len + 1 THEN
      p_temp := SUBSTR( i_str, p_start, c_len - p_start + 1 ) || i_delim;
      IF INSTR( p_result, i_delim || p_temp ) = 0 THEN
        p_result := p_result || p_temp;
      END IF;
    END IF;
  END IF;
  RETURN SUBSTR( p_result, c_ld + 1, LENGTH( p_result ) - 2 * c_ld );
END;
/

SELECT your_list_column,
       remove_Duplicates_From_List( your_list_column ) AS uniq
FROM   your_table

| YOUR_LIST_COLUMN |      UNIQ |
|------------------|-----------|
|        a,a,b,c,d |   a,b,c,d |
|        a,b,a,c,d |   a,b,c,d |
|        a,b,c,d,a |   a,b,c,d |
|        a,b,b,c,d |   a,b,c,d |
|        a,b,c,b,d |   a,b,c,d |
|        a,b,c,d,b |   a,b,c,d |
|        a,b,c,d,d |   a,b,c,d |
|        a,b,a,c,b |     a,b,c |
|        a,b,c,d,e | a,b,c,d,e |

永远不要将数据存储为逗号分隔的项。这只会给您带来很多麻烦。@jarlh这是一个临时表，用于将数据加载到主表。您需要检查字符串是否包含重复的值，还是获取另一个字符串，仅包含非重复的值？如果是，您需要保留初始字符串的顺序吗？@Aleksej我需要得到一个没有重复或不重复字符串的字符串，不需要保留顺序。谢天谢地，永远不要将数据存储为逗号分隔的项目。这只会给您带来很多麻烦。@jarlh这是一个临时表，用于将数据加载到主表。您需要检查字符串是否包含重复的值，还是获取另一个字符串，仅包含非重复的值？如果是这样，您需要保留初始字符串的顺序吗？@Aleksej我需要得到一个没有重复或非重复字符串的字符串，不需要保留顺序。谢谢谢谢，如何从列中获取唯一值？@user75ponic什么列？您是指列表中的唯一值吗？@user75ponic Updated-更好的解决方案是不将列表存储为字符串并将列表项放入单独的表中。感谢更新，但我仍然可以看到重复的值。@user75ponic请用a更新您的问题-我没有您的数据，无法看到您的查询，也不知道为什么您仍然看到重复的查询，因为我发布的查询适用于我的示例数据。谢谢，我如何从列中获取唯一值？@user75ponic什么列？您是指列表中的唯一值吗？@user75ponic Updated-更好的解决方案是不将列表存储为字符串并将列表项放入单独的表中。感谢更新，但我仍然可以看到重复的值。@user75ponic请用a更新您的问题-我没有您的数据，无法看到您的查询，也不知道为什么您仍然看到重复的查询，因为我发布的查询适用于我的示例数据。