Question

我正在写一个包含几个子查询的选择（下面的代码片段中只有一个），但是我很难返回仅在AIRFI_TCD子查询中有1个现有行的行。我只希望在TSUMM和TPPPRFL表上有匹配的CLT_ID时显示行。我尝试了HAVING COUNT子句（请参见下文），但这没有用。我正在空缺如何将TSUMM与子查询一起使用。

      SELECT RIGHT(DIGITS (A.CLT_ID),9) ||  A.PGM_ID ||
         RIGHT(DIGITS (A.PGM_ACCT_SQNBR),4) AS BN
       , ( SELECT B.XREF_NBR
           FROM GHMTUO#1.TPPPRFL B
           WHERE B.PARTIC_PRFL_TCD = '04' --AIRFI
             AND B.CLT_ID = A.CLT_ID
             AND B.BUS_PGM_ID = A.PGM_ID
             AND B.CLT_ID_TCD = '01'
             AND B.PARTIC_PRFL_EDT = (SELECT MAX(X.PARTIC_PRFL_EDT)
                                      FROM GHMTUO#1.TPPPRFL X
                                      WHERE X.CLT_ID = B.CLT_ID)
             AND B.PARTIC_PRFL_CDTTM = (SELECT MAX(Z.PARTIC_PRFL_CDTTM)
                                        FROM GHMTUO#1.TPPPRFL Z
                                        WHERE Z.CLT_ID = B.CLT_ID)
          ) AS AIRFI_TCD
  FROM RAMTUO#1.TSUMM A
  WHERE A.PGM_ID = 'RT'
  GROUP BY A.CLT_ID, A.PGM_ID, A.PGM_ACCT_SQNBR
  HAVING COUNT(AIRFI_TCD) > 1
  WITH UR;

谢谢！

Answer 1

这是内部联接解决方案吗？

SELECT RIGHT(DIGITS (A.CLT_ID),9) ||  A.PGM_ID ||
         RIGHT(DIGITS (A.PGM_ACCT_SQNBR),4) AS BN,
       B.XREF_NBR AS AIRFI_TCD
FROM RAMTUO#1.TSUMM A INNER JOIN GHMTUO#1.TPPPRFL B ON B.CLT_ID = A.CLT_ID AND B.BUS_PGM_ID = A.PGM_ID
WHERE A.PGM_ID = 'RT' AND B.PARTIC_PRFL_TCD = '04'
   AND ...
GROUP BY A.CLT_ID, A.PGM_ID, A.PGM_ACCT_SQNBR

仅当存在匹配的CLT_ID和匹配的PGM_ID时才会显示行

Answer 2

如果您只需要存在，请尝试以下操作：

  SELECT RIGHT(DIGITS (A.CLT_ID),9) ||  A.PGM_ID ||
         RIGHT(DIGITS (A.PGM_ACCT_SQNBR),4) AS BN
  FROM RAMTUO#1.TSUMM A
  WHERE A.PGM_ID = 'RT'
  AND EXISTS 
        (
           SELECT 1
           FROM GHMTUO#1.TPPPRFL B
           JOIN 
           (
             SELECT CL
               T_ID
             , MAX(PARTIC_PRFL_EDT) PARTIC_PRFL_EDT
             , MAX(PARTIC_PRFL_CDTTM) PARTIC_PRFL_CDTTM
             FROM GHMTUO#1.TPPPRFL
             GROUP BY CLT_ID
           ) X ON X.CLT_ID = B.CLT_ID 
              AND X.PARTIC_PRFL_EDT = B.PARTIC_PRFL_EDT
              AND X.PARTIC_PRFL_CDTTM = B.PARTIC_PRFL_CDTTM
           WHERE B.PARTIC_PRFL_TCD = '04' --AIRFI
             AND B.CLT_ID = A.CLT_ID
             AND B.BUS_PGM_ID = A.PGM_ID
             AND B.CLT_ID_TCD = '01'
        )
  ;

Answer 3

我特别喜欢DB2的一件事是能够通过JOIN TABLE（...）将复杂的表达式甚至子查询移到新的虚拟数据字段中，如下所示：

      SELECT RIGHT(DIGITS (A.CLT_ID),9) ||  A.PGM_ID ||
         RIGHT(DIGITS (A.PGM_ACCT_SQNBR),4) AS BN
       , subq.AIRFI_TCD
  FROM RAMTUO#1.TSUMM A
    INNER JOIN TABLE
       ( SELECT B.XREF_NBR,
                COUNT(*)OVER() AS total_amount --number of matching entries
           FROM GHMTUO#1.TPPPRFL B
           WHERE B.PARTIC_PRFL_TCD = '04' --AIRFI
             AND B.CLT_ID = A.CLT_ID
             AND B.BUS_PGM_ID = A.PGM_ID
             AND B.CLT_ID_TCD = '01'
             AND B.PARTIC_PRFL_EDT = (SELECT MAX(X.PARTIC_PRFL_EDT)
                                      FROM GHMTUO#1.TPPPRFL X
                                      WHERE X.CLT_ID = B.CLT_ID)
             AND B.PARTIC_PRFL_CDTTM = (SELECT MAX(Z.PARTIC_PRFL_CDTTM)
                                        FROM GHMTUO#1.TPPPRFL Z
                                        WHERE Z.CLT_ID = B.CLT_ID)
          ) AS subq (AIRFI_TCD, total_amount) ON subq.total_amount = 1 --instead of HAVING
  WHERE A.PGM_ID = 'RT'
  WITH UR;

尝试一下，希望它能起作用。

内部联接多个子查询？

3 个答案: