Hi all -- I just need a quick sanity check on a query.
I have two tables:
CREATE TABLE users (
userID VARCHAR(10) NOT NULL PRIMARY KEY,
[many other fields]
)
CREATE TABLE subscriptions (
userID VARCHAR(10) NOT NULL,
listID INT NOT NULL
)
In these tables, users.userID == subscriptions.userID.
The users table keeps 1 record per userID, and the subscriptions table keep
multiple records per userID (one for each listID to which they're
subscribed).
If I wanted to select all users from the users table that *do not* appear in
the subscriptions table, I'd want the following query:
SELECT users.*
FROM users
LEFT JOIN subscriptions
ON users.userID=subscriptions.userID
WHERE subscriptions.userID IS NULL
Correct?
I know that this is a pretty base example, but I'd like to confirm it
(outside of an example in a book) with someone a bit more knowledgable than
me. There are a couple other reports here that calculate this number in
other ways, and I'd like to be able to positively state that this is the
be-all end-all for the needed data.
Much thanks!
--
denonymous
www.coldcircuit.net
denonymous.ne.mediaone.net
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