help with sql query with parentheses

Question

i have following code:

SELECT *
FROM table
WHERE thread = $thread
AND (user != $user1 OR user != $user2)

i want the code to pick all rows that contains $thread BUT the user isn't $user1 or $user2.

is my code correct? or should it be like:

SELECT *
FROM table
WHERE thread = $thread
(AND user != $user1 OR user != $user2)

thanks in advance

Answer 1

Use this:

SELECT *
FROM table
WHERE thread = $thread
(AND user != $user1 AND user != $user2)

Because you don't want if the user is either of user1 or user2, for this reason using 'AND' will be proper option here.

Also if the $thread is not an integer field, you need enclose it in quotes eg:

WHERE thread = '$thread'

Answer 2

SELECT *
FROM table
WHERE thread = $thread
AND user != $user1
AND user != $user2

Answer 3

I think you should also be using <> instead of !=

So:

SELECT *
FROM table
WHERE thread = $thread
AND user <> $user1
AND user <> $user2

Answer 4

Use:

SELECT t.*
  FROM TABLE t
 WHERE t.thread = mysql_real_escape_string($thread)
   AND t.user NOT IN (mysql_real_escape_string($user1), mysql_real_escape_string($user2))

Please use mysql_real_escape_string, or risk SQL injection attacks.

Answer 5

You could also use

SELECT *
FROM table
WHERE thread = '$thread'
AND user NOT IN ($user1, $user2)

Don't know which executes faster, but this is my preferred way because I like it's readability better.