Question

我有像这样的查询

SELECT  f.ACCOUNT_ID,
        f.TGL,
        p.ACCOUNT_EMAILADDRESS


     FROM distributor_kokola.forecast f
      inner join distributor_kokola.push_distributor p on p.ACCOUNT_ID = f.ACCOUNT_ID
      where f.ACCOUNT_ID NOT IN(

                 select ACCOUNT_ID
                        from distributor_kokola.forecast
                         where DATE_FORMAT(TGL, "%Y-%m") = DATE_FORMAT(CURDATE(), "%Y-%m")  
                         group by ACCOUNT_ID


    )

      group by f.ACCOUNT_ID;

Sub Query工作但是要慢，所以我用Left Join更改它，它运行得更快

SELECT  f.ACCOUNT_ID,
        f.TGL,
        p.ACCOUNT_EMAILADDRESS


     FROM distributor_kokola.forecast f
       left  join(

                 select ACCOUNT_ID
                        from distributor_kokola.forecast
                         where DATE_FORMAT(TGL, "%Y-%m") = DATE_FORMAT(CURDATE(), "%Y-%m")  
                         group by ACCOUNT_ID


    )subb on subb.ACCOUNT_ID = f.ACCOUNT_ID

       inner join distributor_kokola.push_distributor p on p.ACCOUNT_ID = f.ACCOUNT_ID
      group by f.ACCOUNT_ID;

但是，我的问题仍然是包含错误结果，

使用Not IN，查询1选择NOT IN query 2。

如何通过左连接获得NOT IN查询。

任何人都可以帮助我吗？

感谢。

Answer 1

您必须添加WHERE子句，以便根据LEFT JOIN的结果进行过滤。如果添加适当的WHERE子句WHERE subb.ACCOUNT_ID IS NULL，它应该按预期工作（因为您在子查询中使用了GROUP BY，没有重复行的危险）：

SELECT  f.ACCOUNT_ID,
        f.TGL,
        p.ACCOUNT_EMAILADDRESS
     FROM distributor_kokola.forecast f
       left  join(
                 select ACCOUNT_ID
                        from distributor_kokola.forecast
                         where DATE_FORMAT(TGL, "%Y-%m") = DATE_FORMAT(CURDATE(), "%Y-%m")  
                         group by ACCOUNT_ID
    )  subb on subb.ACCOUNT_ID = f.ACCOUNT_ID
       inner join distributor_kokola.push_distributor p on p.ACCOUNT_ID = f.ACCOUNT_ID
      WHERE sub.ACCOUNT_ID IS NULL
      group by f.ACCOUNT_ID;

<强>更新

我们LEFT JOIN的目标是找到forecast表中所有在子查询中没有匹配行的行。因此，我们需要一个WHERE子句来删除具有匹配行的所有行 - WHERE sub.ACCOUNT_ID IS NULL非常适合。

SO用户@quassnoi写了一个wonderful comparison of different methods来实现这个目标。

子查询不是IN与左连接替代？

1 个答案: