calculate the percentage total in completed tasks mysql

Question

I need to group and get the percentage completed in true in a MySQL query

id type completed
1   4    true
2   4    false
3   3    false
4   5    true
5   5    true

Result

type   completed
4        %50
3        %0
5        %100

Answer 1

Try using conditional aggregation:

SELECT
    type,
    100.0 * AVG(completed = 'true') AS completed
FROM yourTable
GROUP BY
    type;

Demo