求一语句

[victorji]

Table T1(a,b)

T1的记录为
a b
ss 1
cc 1
dd 1
ss 1
dd 1
ss 1

我想统计查询一下表T1的结果为:
a b
ss 3
cc 1
dd 2

请问sql语句改怎么写

[CrazyFor]

select a,count(*) as count_A from t1 group by a

[cysh]

楼上完正确!

[伍子V5]

select a,sum(1) as b from T1 group by a

[Dennis618]

樓主的問題有點含糊,是要統計a字段值出現的次數還是a字段相同時b字段值的總和呢?
--b的總和
select a,sum(b) as b from T1 group by a
--a出現的次數
select a,sum(1) as b from T1 group by a

[welyngj]

select a,sum(b)as b from t1 group by a

[pengdali]

select a,sum(b) b from t1 group by a

[maoyesky]

select a,b from cc where a in (select a from cc group by a having (count(a) = 1))
union select a,cast(count(*) as varchar(20)) as numbers from cc group by a having (count(*) > 1)