[mysql] Using group by on two fields and count in SQL

I have a table in my mysql db that has two columns: group and subgroup. See below.

 group, subGroup
 grp-A, sub-A
 grp-A, sub-A
 grp-A, sub-B      
 grp-B, sub-A
 grp-B, sub-B
 grp-B, sub-B

I am trying to get the number of records for each unique couple group/subGroup.

This is what I expect:

group, subGroup, count
grp-A, sub-A, 2
grp-A, sub-B, 1
grp-B, sub-A, 1
grp-B, sub-B, 2

After reading some posts I tried several sql queries using group by, count(), but I do not manage to get the expected result. How can I fix this?

You must group both columns, group and sub-group, then use the aggregate function COUNT().

SELECT
  group, subgroup, COUNT(*)
FROM
  groups
GROUP BY
  group, subgroup

SELECT group,subGroup,COUNT(*) FROM tablename GROUP BY group,subgroup