There is faster way how to determine total number of rows in table, then in all tables as well. If you have primary key on your table (so it doesn't works that simply for heap tables) you can just simply select rowcnt column on sysindexes where id = objectid('yourtable') and indid = 1.

This gives you number of rows in your primary key, which is the number of rows in your table. Subsequently if all tables in your database has a PK, just simply sum all rowcnt columns in sysindexes table.

Jan