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
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select x , count(*) from tb group by x
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select col , count(*) from x group by col
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- 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）*/
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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'
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select col, [count] = case col when 'true' then count(col) else count(col) end
from X
group by col
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- SQL code
select col,count(1) from x group by col