mysql - 在子查询中使用主查询中的列时出错

Question

我不是 mysql 的高级用户，所以您必须多多包涵。

我试图在其中一个子查询中使用 cref 变量，但我收到一个错误，指出 cref 列不存在。如果我取出子查询，它将显示该列，因此该列肯定存在。

如果还有其他错误，请多多指教:)

SELECT DISTINCT
  (contractorsRef) AS cref,
  RIDGROUP AS ridg,
  (
    SELECT count(*) FROM (
      SELECT DISTINCT subcontractorRef
      FROM request
      INNER JOIN request_config
        ON request_config.RIDGROUP = request.RIDGROUP
      WHERE request_config.contractorsRef = cref  --### ERROR HERE
        AND currenttaxyear =2011
        AND weekno =31
  ) AS xx
) as xxx
FROM request_config
WHERE currenttaxyear =2011
  AND weekno =32
  AND contractorsRef <>132

Answer 1

试试这个(请注意，我在外部选择中将 request_config 标记为 outer_config 并且我在内部选择中使用标签限定了引用

SELECT DISTINCT (contractorsRef) AS cref, RIDGROUP AS ridg, 
    (select count(DISTINCT subcontractorRef)
    FROM request
    INNER JOIN request_config ON request_config.RIDGROUP = request.RIDGROUP
    WHERE request_config.contractorsRef = outer_config.contractorsRef 
    AND currenttaxyear =2011
    AND weekno =31) AS xxx
FROM request_config outer_config
WHERE currenttaxyear =2011
AND weekno =32
AND contractorsRef <>132

编辑 请再试一次，我从子选择中删除了 1 个不必要的层