Question

我正在尝试编写一个子查询以包含更大的查询，我正在编写的子查询需要从主列获取a.workorder_id

这个有用（注意x.workorder_id ='805'）

SELECT a.* , 
( SELECT SUM( maxes ) qty 
  FROM  ( 
     SELECT MAX( qty ) maxes 
     FROM `rework_line` x 
     WHERE x.workorder_id = '805' 
     GROUP BY x.size 
  ) as tba 
) tmpsum 
FROM rework_line a 
WHERE a.workorder_id = '805' 
GROUP BY a.workorder_id

然而，当我更改x.workorder_id = a.workorder_id时，它不再起作用并告诉我

＃1054 - 'where子句'中的未知列'a.workorder_id'

SELECT a.* , 
( SELECT SUM( maxes ) 
  qty FROM  ( 
     SELECT MAX( qty ) maxes 
     FROM `mtborah_rework_line` x 
     WHERE x.workorder_id = a.workorder_id 
     GROUP BY x.size 
  ) as tba 
) tmpsum 
FROM mtborah_rework_line a 
WHERE a.workorder_id = '805' 
GROUP BY a.workorder_id

我确信这很简单，我忘记了，但是在我所有的googing中我都找不到怎么做，我也试着在freenode的mysql房间里询问，而他们所说的只是将它重写为加入，这是不可能的，因为我有它的查询如果我重新加入这个表它将通过我的计数和总和

Answer 1

也许我错过了一些东西，但为什么不用连接中的子查询而不是相关的子查询来重写它：

SELECT a.*, qty
FROM mtborah_rework_line a 
LEFT JOIN
(
  SELECT SUM(maxes) qty, workorder_id
  FROM
  (
    SELECT MAX( qty ) maxes, x.workorder_id
    FROM `mtborah_rework_line` x 
    GROUP BY x.size, x.workorder_id
  ) m
  GROUP BY workorder_id
) q
  on a.workorder_id = q.workorder_id
WHERE a.workorder_id = '805';

甚至这样：

SELECT a.*, SUM(maxes) qty
FROM mtborah_rework_line a 
LEFT JOIN
(
  SELECT MAX(qty) maxes, x.workorder_id
  FROM `mtborah_rework_line` x 
  GROUP BY x.size, x.workorder_id
) q
  on a.workorder_id = q.workorder_id
WHERE a.workorder_id = '805' 
GROUP BY a.workorder_id;

访问子查询中的父列信息

1 个答案: