t1:
name age
a 20
b 30
c 40
...t2:
name login_time
a 15:00
b 16:10
a 19:30
a 22:55
...现select t1.name,age,login_time from t1,t2 where t1.name=t2.name
得:
name age login_time
a 20 15:00
a 20 19:30
a 20 22:55但我只想要其中一条就够了(即只要有a的记录即可达到目的),请问select如何写呢?谢谢
name age
a 20
b 30
c 40
...t2:
name login_time
a 15:00
b 16:10
a 19:30
a 22:55
...现select t1.name,age,login_time from t1,t2 where t1.name=t2.name
得:
name age login_time
a 20 15:00
a 20 19:30
a 20 22:55但我只想要其中一条就够了(即只要有a的记录即可达到目的),请问select如何写呢?谢谢
declare @t2 table(name varchar(10),login_time varchar(10))
insert @t1
select 'a',20 union all
select 'b',30 union all
select 'c',40
insert @t2
select 'a','15:00' union all
select 'b','16:10' union all
select 'a','19:30' union all
select 'a','22:55'select a.name,a.age,b.login_time from @t1 a
left join (select name,min(login_time) as login_time from @t2 group by name) b
on a.name = b.name
select a.name,a.age,b.login_time from @t1 a
INNER join (select name,min(login_time) as login_time from @t2 group by name) b
on a.name = b.name
declare @t1 table(name varchar(10),age int)
declare @t2 table(name varchar(10),login_time varchar(10))
insert @t1
select 'a',20 union all
select 'b',30 union all
select 'c',40
insert @t2
select 'a','15:00' union all
select 'b','16:10' union all
select 'a','19:30' union all
select 'a','22:55'select A.name,A.age,B.login_time from @t1 A,@t2 B where A.name=B.name
and A.name='a' --加上一个过滤条件就可以了