How to use Count condition in sql query

Question

How can I use count condition in sql query. Here is my query

SELECT COUNT(test='maths') FROM homework where id = 1;

juergen d · Accepted Answer · 2016-05-06 10:08:37Z

4

In MySQL conditions have either 1 or 0 as outcome. So use sum() instead

SELECT sum(test='maths') FROM homework where id = 1;

count() just counts non-null values. So you could do it with count() too but like this

SELECT count(case when test='maths' then 1 else null end) 
FROM homework 
where id = 1;

answered May 6, 2016 at 10:08

juergen d

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