MySQL syntax for count

Posted on 2011-09-28
Last Modified: 2012-05-12
I want to count records in a table that satisfying a condition.  But I also want to output a zero if there is no such record.  For example

id   col1    col2    
1    a        5
2    b        0
3    c        2        
4    a       12

The query
select col1, count(*) from tab where col2 > 0 group by 1;
would return
a  2
c  1

I want the put put to also show
b   0

How do I do this?

Question by:cpeters5
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LVL 41

Expert Comment

ID: 36717101
select col1, sum(case when col2 > 0 then 1 else 0 end)
from tab group by col1

Author Comment

ID: 36717121
Thanks ralmada
LVL 41

Accepted Solution

ralmada earned 500 total points
ID: 36717126

select col1, sum(if(col2 > 0,1,0))
from tab group by col1

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