求SQL查询语句。在线等

select a_id,count(distinct checkdate) 天数 from tt_a group by a_id

create table A(a_id int, checkdate varchar(10) , checktime varchar(10) )

insert into A values(1, '2008-02-01', '08:00:00') 

insert into A values(1, '2008-02-01', '17:00:00') 

insert into A values(1, '2008-02-03', '08:00:00') 

insert into A values(1, '2008-02-03', '13:00:00') 

insert into A values(1, '2008-02-03', '17:00:00') 

insert into A values(1, '2008-02-04', '17:00:00') 

insert into A values(2, '2008-02-11', '08:00:00') 

insert into A values(2, '2008-02-11', '17:00:00') 

insert into A values(2, '2008-02-13', '08:00:00') 

insert into A values(3, '2008-02-23', '13:00:00') 

insert into A values(4, '2008-02-03', '17:00:00') 

insert into A values(4, '2008-02-04', '17:00:00') 

go



select a_id , count(distinct checkdate) 天数 from A group by a_id order by a_id

/*

a_id        天数          

----------- ----------- 

1           3

2           2

3           1

4           2



（所影响的行数为 4 行）

*/



select a_id , count(*) 天数 from (select distinct a_id , checkdate from A) t group by a_id order by a_id

/*

a_id        天数          

----------- ----------- 

1           3

2           2

3           1

4           2



（所影响的行数为 4 行）

*/



drop table A

select a_id, count(distinct convert(varchar(10),checkdate,120)) from a

group by a_id

select a_id , count(*) 天数 from (select distinct a_id , checkdate from a) t group by a_id