语句1:
select T1a,T1b,(select T2a from table2 where table2.T2b=table1.T1c ) as T2a from table1
与
语句2:
select T1a,T1b,table2.T2a from table1 inner join table2 on table2.T2b=table1.T1c
等不等价
语句1:
select T1a,T1b,(select T2a from table2 where table2.T2b=table1.T1c ) as T2a from table1
与
语句2:
select T1a,T1b,table2.T2a from table1 inner join table2 on table2.T2b=table1.T1c
等不等价