處理MySQL的子查詢返回多行

Question

這裏是我的例子：

select row_x from table_1 where row_y = (select row_a from table_2 where row_b = x) 

是我遇到的問題是，我的查詢需要，如果子查詢返回多行返回多行。

理想的情況下，將轉化爲類似於：

'select row_x from table_1 where row_y = '<first row from subquery>' or row_y = '<second row from subquery>' etc. 

我怎樣才能做到這一點？謝謝！

Answer 1

您正在尋找IN子句

select row_x from table_1 
where row_y 
IN (
    select row_a from table_2 where row_b = x 
    ) 

Answer 2

SELECT t1.row_x FROM table_1 t1 JOIN table_2 t2 ON t1.row_y=t2.row_a WHERE t2.row_b = x