Plsql pl/sql：将行聚合为varchar？

结果是：

如何将

和

和行聚合为varchar，以获得以下预期结果：

SELECT concat(concat('m.', COLUMN_NAME), concat(' = mtf.', COLUMN_NAME)) A
 FROM all_tab_columns
where table_name like 'T_EMPLOYEE' 

试试这个。这可能会有帮助

由于11G，您可以使用该函数

-------------------------------PLSQL Starts-----------------------------------------

set serveroutput on;
DECLARE
lv_cond LONG;
BEGIN
FOR i IN (
SELECT
  CASE
    WHEN ROWNUM =1
    THEN 'WHERE '
      ||concat(concat('m.', COLUMN_NAME), concat(' = mtf.', COLUMN_NAME))
    ELSE 'AND '
      ||concat(concat('m.', COLUMN_NAME), concat(' = mtf.', COLUMN_NAME))
  END col1
FROM all_tab_columns
WHERE table_name = 'EMP_V1') LOOP
lv_cond:=lv_cond||' '||i.col1;
END LOOP;
dbms_output.put_line(lv_cond);
END;

-------------------------------PLSQL Ends-----------------------------------------

SELECT
  CASE
    WHEN ROWNUM =1
    THEN 'WHERE '
      ||concat(concat('m.', COLUMN_NAME), concat(' = mtf.', COLUMN_NAME))
    ELSE 'AND '
      ||concat(concat('m.', COLUMN_NAME), concat(' = mtf.', COLUMN_NAME))
  END
FROM all_tab_columns
WHERE table_name = 'EMP_V1' ;

---------------------------------OUTPUT---------------------------------------------

COL1
WHERE m.EMPNO = mtf.EMPNO
AND m.ENAME = mtf.ENAME
AND m.JOB = mtf.JOB
AND m.MGR = mtf.MGR
AND m.HIREDATE = mtf.HIREDATE
AND m.SAL = mtf.SAL
AND m.COMM = mtf.COMM
AND m.DEPTNO = mtf.DEPTNO
AND m.NEWADD = mtf.NEWADD
------------------------------------------------------------------------------------

• 我使用了

  |

  进行varchar连接（对我来说看起来有点干净）

• CHR（13）| | CHR（10）

  是CRLF

• 组内（按列ID排序）

  指定收集行以进行连接的顺序

---

我能知道如何合并成存储所有行的字符串吗@AvrajitRoyI使用PLSQL方法修改了答案，将其存储到变量中。你可以用VARCHAR2代替LONG。嘿，我可以知道为什么这个答案得到-15。concat函数不常用。通常的方法是级联运算符

| |

。特别是因为这样就不需要嵌套函数调用。查询的第一行是：

SELECT'm.| | | COLUMN| | | NAME'=mtf.| | COLUMN|u NAME A

-------------------------------PLSQL Starts-----------------------------------------

set serveroutput on;
DECLARE
lv_cond LONG;
BEGIN
FOR i IN (
SELECT
  CASE
    WHEN ROWNUM =1
    THEN 'WHERE '
      ||concat(concat('m.', COLUMN_NAME), concat(' = mtf.', COLUMN_NAME))
    ELSE 'AND '
      ||concat(concat('m.', COLUMN_NAME), concat(' = mtf.', COLUMN_NAME))
  END col1
FROM all_tab_columns
WHERE table_name = 'EMP_V1') LOOP
lv_cond:=lv_cond||' '||i.col1;
END LOOP;
dbms_output.put_line(lv_cond);
END;

-------------------------------PLSQL Ends-----------------------------------------

SELECT
  CASE
    WHEN ROWNUM =1
    THEN 'WHERE '
      ||concat(concat('m.', COLUMN_NAME), concat(' = mtf.', COLUMN_NAME))
    ELSE 'AND '
      ||concat(concat('m.', COLUMN_NAME), concat(' = mtf.', COLUMN_NAME))
  END
FROM all_tab_columns
WHERE table_name = 'EMP_V1' ;

---------------------------------OUTPUT---------------------------------------------

COL1
WHERE m.EMPNO = mtf.EMPNO
AND m.ENAME = mtf.ENAME
AND m.JOB = mtf.JOB
AND m.MGR = mtf.MGR
AND m.HIREDATE = mtf.HIREDATE
AND m.SAL = mtf.SAL
AND m.COMM = mtf.COMM
AND m.DEPTNO = mtf.DEPTNO
AND m.NEWADD = mtf.NEWADD
------------------------------------------------------------------------------------

SELECT LISTAGG(
         'm.' || COLUMN_NAME || ' = ' || 'mtf.' || COLUMN_NAME,
         CHR(13) || CHR(10) || 'AND ')
       WITHIN GROUP (ORDER BY COLUMN_ID)  A
FROM all_tab_columns
where table_name like 'T_EMPLOYEE'