MYSQL query two tables (JOIN) . is there a way to match only 1 entry ( 2nd table might have multiple matches)?

If you want to display a record only when there is at least one matching record in the second table then you can use INNER JOIN.

If you want to return only one record even if there are multiple records in the second table then you may want to use a subquery, for example:

SELECT userid, firstname, lastname

FROM TABLE1

WHERE id in (Select userid FROM TABLE2)

SELECT [column fields that you want to retrieve] FROM table1 INNER JOIN table2 ON table1.primarykey = table2.foreignkey INNER JOIN table3 ON table2.primarykey = table3.foreignkey INNER JOIN table4 ON table3.primarykey = table4.foreignkey INNER JOIN table5 ON table4.primarykey = table5.foreignkey WHERE field = yourcriteria you can continue on. primary key is the first table's key and foreign key is the reference field if you want to get records with no matching records from other table you use an OUTER JOIN LEFT OUTER JOIN table6 ON table5.primarykey = table6.foreignkey you get the idea. ;)

$query = "SELECT * FROM table1, table2 WHERE table1.email = table2.email AND table2.email = 'example@email.com'"

that query should be able to find the email address in table2 and get the information from table1 that matches it.

that what your after?

use mysql_num_rows($query) to get the number of rows.