sql - 使用什么 SQL 函数而不是 UNION 来只有一个条件？

Question

我需要缩短这个 SQL 请求。我应该使用 JOIN 吗？
UNION 之间的一切都相同，但表名不同。

UPD:是否可以只对所有表使用一组条件？

SELECT column1, column2, column3, COUNT(*) FROM TABLE_1 WHERE
(condition1)
AND
(condition2)

GROUP BY column1, column2, column3

UNION

...                                              (N times)

UNION

SELECT column1, column2, column3, COUNT(*) FROM TABLE_N WHERE
(condition1)
AND
(condition2)

GROUP BY column1, column2, column3

ORDER BY column1, column2, column3;

Answer 1

您的查询可以写为:

SELECT column1, column2, column3, COUNT(*)
FROM ((SELECT column1, column2, column3, 1 as which
       FROM TABLE_1
      ) UNION ALL
      (SELECT column1, column2, column3, 2 as which
       FROM TABLE_2
      ) UNION ALL
      . . .
     ) t
WHERE (condition1) AND
      (condition2)
GROUP BY column1, column2, column3, which;