EoghanM EoghanM - 6 months ago 15
SQL Question

postgresql - sql - count of `true` values

myCol
------
true
true
true
false
false
null


In the above table, if I do :

select count(*), count(myCol);


I get
6, 5


I get
5
as it doesn't count the null entry.

How do I also count the number of true values (3 in the example)?

(This is a simplification and I'm actually using a much more complicated expression within the count function)

Edit summary: I also want to include a plain count(*) in the query, so can't use a where clause

Answer
SELECT COALESCE(sum(CASE WHEN myCol THEN 1 ELSE 0 END),0) FROM <table name>

or, as you found out for yourself:

SELECT count(CASE WHEN myCol THEN 1 END) FROM <table name>
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