12:42:37 SQL> create table t1(a int,b int);表已创建。已用时间: 00: 00: 00.31
12:42:38 SQL> create table t2(a int,b int);表已创建。已用时间: 00: 00: 00.16
12:42:38 SQL>
12:42:38 SQL> select a.a,sum(b.b)
12:42:38 2 from t1 a,t2 b
12:42:38 3 where a.a=b.a
12:42:38 4 group by
12:42:38 5 a.a;未选定行已用时间: 00: 00: 00.47
12:42:38 SQL> create table t2(a int,b int);表已创建。已用时间: 00: 00: 00.16
12:42:38 SQL>
12:42:38 SQL> select a.a,sum(b.b)
12:42:38 2 from t1 a,t2 b
12:42:38 3 where a.a=b.a
12:42:38 4 group by
12:42:38 5 a.a;未选定行已用时间: 00: 00: 00.47
select a.id,max(b.name) from a,b where a.id=b.id
group by a.id
select a.id,b.name from a,b where a.id=b.id
group by a.id,b.name