求一个简单的表查询语句
有一个表，这个表X只有一列，假设为col并且只有两个值：true,false
现在的要求是求出来true,false 各有多少行，
在这里我写了一个，不好：
Select count(*) as tr, (Select count(*) from T where col= false) as fa from T where col= true


[解决办法]
select x , count(*) from tb group by x
[解决办法]
select col , count(*) from x group by col
[解决办法]

SQL code

create table x(col varchar(10))insert into x values('true') insert into x values('true') insert into x values('true') insert into x values('true') insert into x values('false') insert into x values('false') goselect col , count(*) cnt from x group by col--drop table col/*col        cnt         ---------- ----------- false      2true       4（所影响的行数为 2 行）*/
[解决办法]
只有两种的话，不用group也行：
SQL code
select col='true', cnt=count(1) from tb where col='true'union allselect col='false', cnt=count(1) from tb where col='false'
[解决办法]

select col, [count] = case col when 'true' then count(col) else count(col) end  
from X
group by col
[解决办法]
SQL code
select col,count(1) from x group by col