Question

我有3张桌子但是现在我只用2来测试

AccntTbl

         id     accnt      amount       date
        ---------------------------------------
         1       xxx        10.00      1/1/2016
         2       yyy        20.00      1/1/2016
         3       zzz        30.00      1/1/2016

IssuedTbl

         id     accnt      issued       dateIssue
        ------------------------------------------
         1       xxx        5.00        1/10/2016
         1       xxx        5.00        2/14/2016
         2       yyy       10.00        2/15/2016

我希望结果看起来像这个......在JANUARY中

        id     accnt       amount    issued    balance  
      -------------------------------------------------
         1      xxx         10.00     5.00      5.00
         2      yyy         20.00     0.00     20.00
         3      zzz         30.00     0.00     30.00

如果它在FEBRUARY

       id     accnt        amount    issued    balance
      -------------------------------------------------
        1       xxx         10.00     10.00     0.00
        2       yyy         20.00     10.00    10.00
        3       zzz         30.00      0.00    30.00

这是我提出的查询

       SELECT   AccntTbl.id, AccntTbl.accnt, AccntTbl.amount, 
                SUM(IssuedTbl.issued) as issued 
       FROM     AccntTbl LEFT JOIN IssuedTbl 
       ON       AccntTbl.id = IssuedTbl.id
       WHERE    (MONTH(IssuedTbl.dateIssue BETWEEN 1 AND 2)) AND
                (YEAR(AccntTbl.date)= 2016)
       GROUP BY AccntTbl.id, AccntTbl.accnt, AccntTbl.amount

但结果不是我所期望的只有来自1 & 2的id会从结果中显示...我想要显示来自AccntTbl的所有值以及来自IssuedTbl..glad的值从任何帮助..tnx：）

Answer 1

当您使用LEFT OUTER JOIN并且想要从 Right 表中过滤某些记录时，您需要将右表过滤器移至{{1}条件else ON将隐式转换为LEFT OUTER JOIN

为了简短起见，INNER JOIN条款拒绝 WHERE行，NULL为非匹配记录生成

LEFT OUTER JOIN

如何连接仍保留主表中所有值的表

1 个答案: