RE: [PHP-DB] Another SELECTING problem :-(

thanks for that ... I've made some comments within yours... Your getting a lot of errors, because the statement has well a lot of mistakes. Let's start near the beginning, you state: SELECT empid, COUNT(empid) FROM emp_cont , employers, contacts This statement should produce an error, since you didn't tell the database which table to take empid from. A working statement would look like [Dave Watkinson] yeah, but empid inly exists in one of the tables in the FROM argument, so there's no error there SELECT empid, COUNT(empid) FROM emp_cont or SELECT emp_cont.empid, COUNT( emp_cont.empid) FROM emp_cont , employers, contacts The next major error is to use a Count function without the group by. I'm not an SQL guru, but I believe whenever you use count you must also use group by or having so adding a SELECT empid, COUNT(empid) FROM emp_cont GROUP BY empid [Dave Watkinson] yep - that works :-) will correct that. Unfortunately, I think the larger issue is how your trying to find your query. Your query did confuse me a little, so I could be wrong, but technically speaking, if you are trying to locate an employee with more than one record in employee contracts, then there's no need to involve the contracts table within the query. [Dave Watkinson] no - it's employers with more than one contact, hence the names of those tables in the WHERE bit :-) So say I have table Employees that contains empid, name, ssn. Then I have table Employee Contracts that contains, empid, contractid. Assuming that all empid(s) on Employee Contracts have a correlating empid in Employees (which they will if the table was defined properly) then the steps to get what you want are: Step 1: Return a Count of empid SELECT COUNT(empid) AS countid FROM emp_cont GROUP BY empid Step 2: Return employees with more than one contract SELECT empid FROM emp_cont WHERE countid >1 [Dave Watkinson] makes sense You'll note that both step requires a return, which general means a subquery, I believe for MySQL to hanle subqueries you actually have to perform to separate queries. If your not using MySQL then you could write a statement such as: SELECT empid FROM emp_cont WHERE (SELECT COUNT(empid) FROM emp_cont GROUP BY empid) [note statement may need tweaking since I use MySQL and can't test it] that didn't work If your using MySQL, I believe you need to return the results from one, then use the results to find the next. Or you could use PHP to cheat, and return all results, but only display the ones where the count is greater than 1. A subquery is best if your tables are large, returning 1000 results to display 50 wastes time. But if you have under 200 employees, then just use the SQL statement [Dave Watkinson] I *am* using MySQL, but found another way round it - Steve got it right away - I wanted a one-to-many, not a many-to-many, so I just added an employer_id column to the contacts table. D'oh! Thanks anyway .. I'm getting used to GROUP now :-) Cheers Dave Alnisa -- ......................................... Alnisa Allgood Executive Director Nonprofit Tech (ph) 415.337.7412 (fx) 415.337.7927 (url) http://www.nonprofit-techworld.org (url) http://www.nonprofit-tech.org (url) http://www.tech-library.org ......................................... Nonprofit Tech E-Update mailto:nonprofit-tech-subscribe@egroups.com ......................................... applying technology to transform .........................................