Question

我要准备一份来自PHP的三张桌子的报告。表A的主键是彼此相关的表是表B中的外键，表B中的主键是表C中的外键。现在我将从表C和表A中选择数据。表A和表C不直接相互关联

Answer 1

尝试以下查询：

select * from A
inner join B on A.primary_key = B.Foreign_key
inner join C on B.primary_key = C.foreign_key

Here A.primary_key  = A's primary key
Here B.Foreign_key  = A's primary key in B's table
B.primary_key = B's primary key
C.foreign_key = B's primary key in C's table

从三个表准备报告

1 个答案: