Hi,

Firstly i have 2 tables for my websms app.

One table stores just the names of the users groups(like an address book). - wsmsgroups Fields:
userid - users unique id
name - name of group(PK because no duplicates)


The other table store there numbers with name and group for contact. - wsmscontacts

Fields:
userid - users unique id
cgroup - group name
contact - contacts name
cellno - cellular number(PK)

Now my problem:

I need to get the groups that have contacts. A group might exist if it has no contacts. But I only want the groups that have one or more rows in wsmscontacts table.

Thanks

If more than one user can belong to a group then it isn't a good primary key, use userid instead.

Also in your second table if a user can share a cell number with someone else it also isn't a good primary key. It is if no one can share a number.

For your join, use a left outer join and test for not null