T1 于 T2 的表 如下:
------------------------------------------------------------------------------------------
SELECT * FROM T1,T2 (接过为2两表的笛卡儿积) 如下
-----------------------------------------------------------------------------------------------
SELECT * FROM T1,T2 WHERE T1.ID = T2.ID
SELECT * FROM T1 JOIN T2 ON T1.ID = T2.ID
以上两句sql 结果相同:
时间: 2024-07-31 14:13:27