99.9%不能解决的sql
如果一个表有字段type,type有值y or n,怎么用select语句返回一条记录,该记录包含y的总和,n的总和
[解决办法]
select sum(case type when 'y ' then 1 else 0 end) [Y Total],
sum(case type when 'n ' then 1 else 0 end) [N Total] from tb
[解决办法]
--try
select
sum(case when type= 'y ' then 1 else 0 end),
sum(case when type= 'n ' then 1 else 0 end)
from tbName
[解决办法]
create table T(type char(1))
insert T select 'y '
insert T select 'y '
insert T select 'y '
insert T select 'n '
select
y_count=sum(case when type= 'y ' then 1 else 0 end),
n_count=sum(case when type= 'n ' then 1 else 0 end)
from T
--result
y_count n_count
----------- -----------
3 1
(1 row(s) affected)
