使用SQL Server 2008的select语句中具有条件的聚合函数

Question

I have following table:

create table test
(
 cola integer
)

With some data:

cola
-------
0
1
0
2
0
3
0
4
0
5

Here I need to count number of zero's presents in the cola , and also want to sum number of other values which are greater than 0, like sum(1,2,3,4,5) .

My bad try:

select count(cola) as zeros ,sum(cola) as others
from test
where cola = 0 and cola > 0;

Answer 1

You want conditional aggregation:

select sum(case when cola = 0 then 1 else 0 end) as zeros,
       sum(case when cola > 0 then cola else 0 end) as others
from test;

Strictly speaking, the second conditional is not needed, assuming the values are never negative:

select sum(case when cola = 0 then 1 else 0 end) as zeros,
       sum(cola) as others
from test;

Answer 2

this query will count number of zero's presents in the cola, and also sum number of other values which are greater than 0, like sum(1,2,3,4,5)

Answer:

select 
count (case when cola=0 then cola end) as Zeros,
sum (case when cola>0 then cola end) as otherthanzeroes
from test;