如何在mysql中获取列中使用的所有值？_Mysql

如何在mysql中获取列中使用的所有值？

mysql

如何在mysql中获取列中使用的所有值？,mysql,Mysql,我有一个MySQL表，其列和值如下： Column "A": 1, 5, 3, 2, 3, 1, 4, 5, ... Column "B": 11, 15, 10, 12, 13, 14, 15, 10, 11, ... Column "C": .... etc. SELECT GROUP_CONCAT(DISTINCT val ORDER BY val) AS col_values FROM ( SELECT a AS val FROM mytable UNION

我有一个MySQL表，其列和值如下：

Column "A": 1, 5, 3, 2, 3, 1, 4, 5, ...
Column "B": 11, 15, 10, 12, 13, 14, 15, 10, 11, ...
Column "C": .... etc.

SELECT GROUP_CONCAT(DISTINCT val ORDER BY val) AS col_values 
  FROM ( SELECT a AS val FROM mytable 
          UNION 
         SELECT b FROM mytable
          UNION
         SELECT c FROM mytable
       ) v

(SELECT a AS val FROM mytable)
UNION
(SELECT b AS val FROM mytable)
UNION
(SELECT c AS val FROM mytable)
ORDER BY 1

表中有多个列具有重复的数值

我想找出每列中唯一的值。因此，对于列“A”，它将返回1,2,3,4,5

目前，我正在对一列使用此查询：

从表组中按A选择concat（A）
但是我不知道如何对多个列执行此操作
如果您的查询适用于A，那么您可以使用以下方法对A、B、C执行此操作：
SELECT A FROM 
( 
  SELECT A FROM table 
  UNION 
  SELECT B FROM table 
  UNION
  SELECT C FROM table
) e

只要这三列具有兼容的类型
 如果您的查询适用于A，那么您可以使用以下方法对A、B、C进行查询：
SELECT A FROM 
( 
  SELECT A FROM table 
  UNION 
  SELECT B FROM table 
  UNION
  SELECT C FROM table
) e

只要这三列具有兼容的类型
 如果您的查询适用于A，那么您可以使用以下方法对A、B、C进行查询：
SELECT A FROM 
( 
  SELECT A FROM table 
  UNION 
  SELECT B FROM table 
  UNION
  SELECT C FROM table
) e

只要这三列具有兼容的类型
 如果您的查询适用于A，那么您可以使用以下方法对A、B、C进行查询：
SELECT A FROM 
( 
  SELECT A FROM table 
  UNION 
  SELECT B FROM table 
  UNION
  SELECT C FROM table
) e

只要这三列具有兼容的类型
 如果它是一组足够小的值，您可以使用GROUP\u CONCAT
aggregate函数和DISTINCT
关键字
例如：
SELECT GROUP_CONCAT(DISTINCT a ORDER BY a) AS a_values 
     , GROUP_CONCAT(DISTINCT b ORDER BY b) AS b_values 
     , GROUP_CONCAT(DISTINCT c ORDER BY c) AS c_values 
  FROM mytable 

GROUP\u CONCAT
返回的字符串长度受max\u GROUP\u CONCAT\u len
变量（在引用中）的限制，我认为max\u allowed\u packet
也起作用
比较返回到max\u group\u concat\u len
的字符串的长度，看它是否更短，以知道返回字符串没有被静默截断

如果要将所有这些值组合到一个单独的列表中，可以执行以下操作：
Column "A": 1, 5, 3, 2, 3, 1, 4, 5, ...
Column "B": 11, 15, 10, 12, 13, 14, 15, 10, 11, ...
Column "C": .... etc.

SELECT GROUP_CONCAT(DISTINCT val ORDER BY val) AS col_values 
  FROM ( SELECT a AS val FROM mytable 
          UNION 
         SELECT b FROM mytable
          UNION
         SELECT c FROM mytable
       ) v

(SELECT a AS val FROM mytable)
UNION
(SELECT b AS val FROM mytable)
UNION
(SELECT c AS val FROM mytable)
ORDER BY 1

编辑
我被查询中使用的CONCAT
函数弄糊涂了，误读了规范。上面的查询返回一行，并返回一个与OP指定的结果完全相同的结果：
1,2,3,4,5,...

如果要在单独的行上返回每个值，结果如下所示：
val
---
  1
  2
  3
  4
  5

然后，来自Tim3880答案的查询就可以做到这一点，但是外部查询并不是必需的
我想添加一个orderby，并实际编写如下查询：
Column "A": 1, 5, 3, 2, 3, 1, 4, 5, ...
Column "B": 11, 15, 10, 12, 13, 14, 15, 10, 11, ...
Column "C": .... etc.

SELECT GROUP_CONCAT(DISTINCT val ORDER BY val) AS col_values 
  FROM ( SELECT a AS val FROM mytable 
          UNION 
         SELECT b FROM mytable
          UNION
         SELECT c FROM mytable
       ) v

(SELECT a AS val FROM mytable)
UNION
(SELECT b AS val FROM mytable)
UNION
(SELECT c AS val FROM mytable)
ORDER BY 1

编辑
添加了SQL FIDLE，显示如何解释规范（表、列、示例值）以及上面SQL语句的结果。。。一条语句将不同的值作为单独的行返回（上面的查询），另一条语句返回逗号分隔的列表（我的答案中的第一个查询）

如果我们想确定某个值出现在哪个列中
SELECT v.val
     , GROUP_CONCAT(DISTINCT v.col ORDER BY v.col) AS in_cols
     , MAX(v.col='a') AS in_col_a
     , MAX(v.col='b') AS in_col_b
     , MAX(v.col='c') AS in_col_c
  FROM (
         SELECT a AS val, 'a' AS col FROM mytable
         UNION
         SELECT b AS val, 'b' AS col FROM mytable
         UNION
         SELECT c AS val, 'c' AS col FROM mytable
       ) v
 GROUP BY v.val
 ORDER BY v.val

如果它是一组足够小的值，您可以使用GROUP\u CONCAT
聚合函数，并使用DISTINCT
关键字
例如：
SELECT GROUP_CONCAT(DISTINCT a ORDER BY a) AS a_values 
     , GROUP_CONCAT(DISTINCT b ORDER BY b) AS b_values 
     , GROUP_CONCAT(DISTINCT c ORDER BY c) AS c_values 
  FROM mytable 

GROUP\u CONCAT
返回的字符串长度受max\u GROUP\u CONCAT\u len
变量（在引用中）的限制，我认为max\u allowed\u packet
也起作用
比较返回到max\u group\u concat\u len
的字符串的长度，看它是否更短，以知道返回字符串没有被静默截断

如果要将所有这些值组合到一个单独的列表中，可以执行以下操作：
Column "A": 1, 5, 3, 2, 3, 1, 4, 5, ...
Column "B": 11, 15, 10, 12, 13, 14, 15, 10, 11, ...
Column "C": .... etc.

SELECT GROUP_CONCAT(DISTINCT val ORDER BY val) AS col_values 
  FROM ( SELECT a AS val FROM mytable 
          UNION 
         SELECT b FROM mytable
          UNION
         SELECT c FROM mytable
       ) v

(SELECT a AS val FROM mytable)
UNION
(SELECT b AS val FROM mytable)
UNION
(SELECT c AS val FROM mytable)
ORDER BY 1

编辑
我被查询中使用的CONCAT
函数弄糊涂了，误读了规范。上面的查询返回一行，并返回一个与OP指定的结果完全相同的结果：
1,2,3,4,5,...

如果要在单独的行上返回每个值，结果如下所示：
val
---
  1
  2
  3
  4
  5

然后，来自Tim3880答案的查询就可以做到这一点，但是外部查询并不是必需的
我想添加一个orderby，并实际编写如下查询：
Column "A": 1, 5, 3, 2, 3, 1, 4, 5, ...
Column "B": 11, 15, 10, 12, 13, 14, 15, 10, 11, ...
Column "C": .... etc.

SELECT GROUP_CONCAT(DISTINCT val ORDER BY val) AS col_values 
  FROM ( SELECT a AS val FROM mytable 
          UNION 
         SELECT b FROM mytable
          UNION
         SELECT c FROM mytable
       ) v

(SELECT a AS val FROM mytable)
UNION
(SELECT b AS val FROM mytable)
UNION
(SELECT c AS val FROM mytable)
ORDER BY 1

编辑
添加了SQL FIDLE，显示如何解释规范（表、列、示例值）以及上面SQL语句的结果。。。一条语句将不同的值作为单独的行返回（上面的查询），另一条语句返回逗号分隔的列表（我的答案中的第一个查询）

如果我们想确定某个值出现在哪个列中
SELECT v.val
     , GROUP_CONCAT(DISTINCT v.col ORDER BY v.col) AS in_cols
     , MAX(v.col='a') AS in_col_a
     , MAX(v.col='b') AS in_col_b
     , MAX(v.col='c') AS in_col_c
  FROM (
         SELECT a AS val, 'a' AS col FROM mytable
         UNION
         SELECT b AS val, 'b' AS col FROM mytable
         UNION
         SELECT c AS val, 'c' AS col FROM mytable
       ) v
 GROUP BY v.val
 ORDER BY v.val

如果它是一组足够小的值，您可以使用GROUP\u CONCAT
聚合函数，并使用DISTINCT
关键字
例如：
SELECT GROUP_CONCAT(DISTINCT a ORDER BY a) AS a_values 
     , GROUP_CONCAT(DISTINCT b ORDER BY b) AS b_values 
     , GROUP_CONCAT(DISTINCT c ORDER BY c) AS c_values 
  FROM mytable 

GROUP\u CONCAT
返回的字符串长度受max\u GROUP\u CONCAT\u len
变量（在引用中）的限制，我认为max\u allowed\u packet
也起作用
比较返回到max\u group\u concat\u len
的字符串的长度，看它是否更短，以知道返回字符串没有被静默截断

如果要将所有这些值组合到一个单独的列表中，可以执行以下操作：
Column "A": 1, 5, 3, 2, 3, 1, 4, 5, ...
Column "B": 11, 15, 10, 12, 13, 14, 15, 10, 11, ...
Column "C": .... etc.

SELECT GROUP_CONCAT(DISTINCT val ORDER BY val) AS col_values 
  FROM ( SELECT a AS val FROM mytable 
          UNION 
         SELECT b FROM mytable
          UNION
         SELECT c FROM mytable
       ) v

(SELECT a AS val FROM mytable)
UNION
(SELECT b AS val FROM mytable)
UNION
(SELECT c AS val FROM mytable)
ORDER BY 1

编辑
我被查询中使用的CONCAT
函数弄糊涂了，误读了规范。上面的查询返回一行，并返回一个与OP指定的结果完全相同的结果：
1,2,3,4,5,...

如果要在单独的行上返回每个值，结果如下所示：
val
---
  1
  2
  3
  4
  5

然后，来自Tim3880答案的查询就可以做到这一点，但是外部查询并不是必需的
我想添加一个orderby，并实际编写如下查询：
Column "A": 1, 5, 3, 2, 3, 1, 4, 5, ...
Column "B": 11, 15, 10, 12, 13, 14, 15, 10, 11, ...
Column "C": .... etc.

SELECT GROUP_CONCAT(DISTINCT val ORDER BY val) AS col_values 
  FROM ( SELECT a AS val FROM mytable 
          UNION 
         SELECT b FROM mytable
          UNION
         SELECT c FROM mytable
       ) v

(SELECT a AS val FROM mytable)
UNION
(SELECT b AS val FROM mytable)
UNION
(SELECT c AS val FROM mytable)
ORDER BY 1

编辑
添加了SQL FIDLE，显示如何解释规范（表、列、示例值）以及上面SQL语句的结果。。。一条语句将不同的值作为单独的行返回（上面的查询），另一条语句返回逗号分隔的列表（我的答案中的第一个查询）

如果我们想确定某个值出现在哪个列中
SELECT v.val
     , GROUP_CONCAT(DISTINCT v.col ORDER BY v.col) AS in_cols
     , MAX(v.col='a') AS in_col_a
     , MAX(v.col='b') AS in_col_b
     , MAX(v.col='c') AS in_col_c
  FROM (
         SELECT a AS val, 'a' AS col FROM mytable
         UNION
         SELECT b AS val, 'b' AS col FROM mytable
         UNION
         SELECT c AS val, 'c' AS col FROM mytable
       ) v
 GROUP BY v.val
 ORDER BY v.val

如果它是一组足够小的值，您可以使用GROUP\u CONCAT
aggregate