denonymous, Wednesday, March 13, 2002, 9:06:48 PM, you wrote: d> Hi all -- I just need a quick sanity check on a query.
d> I have two tables: d> CREATE TABLE users ( d> userID VARCHAR(10) NOT NULL PRIMARY KEY, d> [many other fields] d> ) d> CREATE TABLE subscriptions ( d> userID VARCHAR(10) NOT NULL, d> listID INT NOT NULL d> ) d> In these tables, users.userID == subscriptions.userID. d> The users table keeps 1 record per userID, and the subscriptions table keep d> multiple records per userID (one for each listID to which they're d> subscribed). d> If I wanted to select all users from the users table that *do not* appear in d> the subscriptions table, I'd want the following query: d> SELECT users.* d> FROM users d> LEFT JOIN subscriptions d> ON users.userID=subscriptions.userID d> WHERE subscriptions.userID IS NULL d> Correct? Looks like it is correct. You can check your query result on any test database. d> I know that this is a pretty base example, but I'd like to confirm it d> (outside of an example in a book) with someone a bit more knowledgable than d> me. There are a couple other reports here that calculate this number in d> other ways, and I'd like to be able to positively state that this is the d> be-all end-all for the needed data. d> Much thanks! -- For technical support contracts, goto https://order.mysql.com/ This email is sponsored by Ensita.net http://www.ensita.net/ __ ___ ___ ____ __ / |/ /_ __/ __/ __ \/ / Victoria Reznichenko / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.net <___/ www.mysql.com --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
