SQL-HELL! How select-query with query for UID / PWD

Gott der Gerechte... SQL macht wahrhaft demütig. I have a mysql-table, containing a field userid as a relation to the field userid in table users. I query this table for all records, using $result = mysqlquery("quarti","SELECT * FROM resume) - ok so far: ----> Now, what, if I want allow the execution of this query only to users with a valid password and userid, as contained in their record in the table users? I have entry variables $uname and $pword in the authentication routine. $result = mysqlquery("quarti","SELECT * FROM product WHERE username.users=$uname, password.users=$pword) What is wrong with the above sql (or what isn´t)? Thanks for a light. Helmut