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MySQL syntax for count

Posted on 2011-09-28
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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

Tab=
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?
pax

0
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Question by:cpeters5
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3 Comments
 
LVL 41

Expert Comment

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

Author Comment

by:cpeters5
ID: 36717121
Perfect!
Thanks ralmada
0
 
LVL 41

Accepted Solution

by:
ralmada earned 500 total points
ID: 36717126
or

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

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