gunakan array/variabel dalam sql-query

Coba ini:

SELECT T2.name,T1.groupName
FROM Table1 T1 INNER JOIN
Table1 T2 on T1.groupID=T2.groupId2
WHERE T2.category=1

Hasil:

NAME    GROUPNAME

Paul    IT
Bob     IT
An      HR

Lihat hasil di SQL Fiddle