Mysql select count values from a single column

Question

A have a column named key - 1,1,2,2,2,2,3 Now i do it with 3 querys:

SELECT count(key) as k FROM `test` WHERE key=1
SELECT count(key) as k FROM `test` WHERE key=2
SELECT count(key) as k FROM `test` WHERE key=3

How to count in one query how many 1,2,3?

Answer 1

Use group by:

SELECT `key`, COUNT(*) FROM `test` GROUP BY `key`;

Answer 2

you can do like this

select count(key) as K FROM test where key in (1,2,3)