sql - 查询子查询

Question

我正在尝试做这样的事情:

SELECT t1.*,
       t2.*
FROM   (SELECT *
        FROM   USER) AS t1,
       (SELECT *
        FROM   t1) AS t2

它在 MySQL 中不起作用。像上面这样的事情可能吗？我的另一个选择是采用最后一个子查询并将其“包装”在主查询周围。想法？

Answer 1

使用:

SELECT t1.*,
       t2.*
  FROM (SELECT *
          FROM USER) AS t1,
       (SELECT *
          FROM (SELECT *
                  FROM USER) AS t1) AS t2

WITH 语法允许您在 CTE 之上构建:

WITH t1 AS (
  SELECT * FROM USER), -- comma separates them
     t2 AS (
  SELECT * FROM t1)
SELECT t1.*, t2.*
  FROM t1, t2

..但是 MySQL 不支持 WITH 子句。