Using group by on two fields and count in SQL

I think you're looking for: SELECT a, b, COUNT(a) FROM tbl GROUP BY a, b

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

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