Question

我的查询如下：

SELECT field
FROM table
WHERE
    (
        SELECT COUNT(*)
        FROM table2
        WHERE table2.field = table.field
    )
    !=
    (
        SELECT COUNT(*)
        FROM table3
        WHERE table3.field = table.field
    )

现在我希望在我的字段列表中包含WHERE个子查询，如：

SELECT field, count1, count2
FROM table
WHERE
    (
        SELECT COUNT(*)
        FROM table2
        WHERE table2.field = table.field
    ) AS Count1
    !=
    (
        SELECT COUNT(*)
        FROM table3
        WHERE table3.field = table.field
    ) AS Count2

这可能吗？当然我可以将这些子查询放在字段列表中，但是我无法比较它们。

有什么想法吗？

Answer 1

如果您使用Sql Server：

，则可以执行此操作

SELECT field, ca2.c2, ca3.c3
FROM table t
cross apply(SELECT COUNT(*) c2
            FROM table2 t2
            WHERE t2.field = t.field)ca2
cross apply(SELECT COUNT(*) c3
            FROM table3 t3
            WHERE t3.field = t.field)ca3
where ca2.c2 <> ca1.c1

Answer 2

使用相关的子选择进行计数。总结在派生表中：

select dt.* from
(
SELECT field,
       (SELECT COUNT(*)
        FROM table2
        WHERE table2.field = table.field) as cnt1,
       (SELECT COUNT(*)
        FROM table3
        WHERE table3.field = table.field) as cnt2
FROM table
) dt
where dt.cnt1 <> dt.cnt2

Answer 3

您只需使用派生表：

select *
from
 (
   SELECT field, 
    (
        SELECT COUNT(*)
        FROM table2
        WHERE table2.field = table.field
    ) AS Count1,
    (
        SELECT COUNT(*)
        FROM table3
        WHERE table3.field = table.field
    ) AS Count2
   FROM table
 ) dt
WHERE Count1 <> Count2

SQL WHERE字段列表中的子查询

3 个答案: