select 中子查询，如何可以查出多个字段

Question

select *,(select sum(0),sum(1) from table1 where pid=tabel2.pid) from tabel2

 

报错：Only one expression can be specified in the select list when the subquery is not introduced with EXISTS.

 

怎么可以 查出2个sum的结果放在表后面呢

Answer 1

你用关联查询，select * from table2 a, (select sum(0),sum(1) from table1 ) b where a.id = b.id