MySQL distinct count if conditions unique

Question

I am trying to build a query that tells me how many distinct women and men there are in a given dataset. The person is identified by a number \'tel\'. It is possible for the sam

Answer 1

Here's one option using a subquery with DISTINCT:

SELECT COUNT(*) gender_count,
   SUM(IF(gender='male',1,0)) male_count,
   SUM(IF(gender='female',1,0)) female_count
FROM (
   SELECT DISTINCT tel, gender
   FROM example_dataset
) t

• SQL Fiddle Demo

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This will also work if you don't want to use a subquery:

SELECT COUNT(DISTINCT tel) gender_count,
    COUNT(DISTINCT CASE WHEN gender = 'male' THEN tel END) male_count,  
    COUNT(DISTINCT CASE WHEN gender = 'female' THEN tel END) female_count
FROM example_dataset

• More Fiddle