Mysql PHP Query Runs Perfectly, But returns as false

Question

I have some mysql_query()s that work just fine, but if I put them in an if else statement they return false. Any idea?

        public function delete_post() {

        $id = $_GET['post_id'];

        mysql_query("DELETE FROM posts WHERE post_id='$id' LIMIT 1");

        if ( !mysql_query() ) {
            echo ('Could not be Deleted');
        } else { 
            echo 'Deleted Successfully'; 
        }
    }

and when i run it, it deletes the post, but returns "Could not be deleted"

The `mysql_*` functions are deprecated. Use `mysqli` or `PDO`. — , Apr 22 '13 at 20:53
Set the query as a variable, and use the variable for your `if()` statement. — Unexpected Pair of Colons, Apr 22 '13 at 20:53
Just a side note, the return of `mysql_query` only returns `true/false` on the success of the SQL query, not if anything was changed after the execution .. — dbf, Apr 22 '13 at 21:06

score 3 · Accepted Answer · answered Apr 22 '13 at 20:53

3

You're running a query with an empty SQL statement, which is not correct SQL. Try this.

$result = mysql_query("DELETE ...");
if (!$result) {
    echo ('Could not be Deleted');
} else {
    echo 'Deleted Successfully';
}

The difference is on line 2 (of my code).

answered Apr 22 '13 at 20:53

mbarlocker

1,310
10
16

You didn't spot the SQL injection. – Sven May 20 '13 at 21:28

Jean · Answer 2 · 2013-04-22T21:01:22.377

2

Note: mysql_query() is deprecated. You really should use PDO::query instead.

If you still wish to use it, do:

$result = mysql_query("DELETE FROM posts WHERE post_id='$id' LIMIT 1");
if (!$result) 
{
    echo ('Could not be Deleted');
}

Explanation:

In you original code you call mysql_query() two times. The second time, there is no argument, so it doesn't work, and that's what your code is reporting.

edited Apr 22 '13 at 21:01

answered Apr 22 '13 at 20:53

Jean

7,623
6
43
58

Thanks's Both of them works :)I was just dumb.. I wanted to do it the shorter way. – Andor Nagy Apr 22 '13 at 20:56

score 1 · Answer 3 · edited May 23 '17 at 12:28

1

I think this is a pretty similar question / answer: What does a successful MySQL DELETE return? How to check if DELETE was successful?

Can you try what it suggests and see if that will work for you?

edited May 23 '17 at 12:28

Community

1
1

answered Apr 22 '13 at 20:54

anotherBob

33
10

score 0 · Answer 4 · answered Apr 22 '13 at 20:54

0

You could try :

public function delete_post() {

        $id = $_GET['post_id'];

        $query = mysql_query("DELETE FROM posts WHERE post_id='$id' LIMIT 1");

        if ( !$query ) {
            echo ('Could not be Deleted');
        } else { 
            echo 'Deleted Successfully'; 
        }
    }

answered Apr 22 '13 at 20:54

RelevantUsername

1,270
8
14

You didn't spot the SQL injection. – Sven May 20 '13 at 21:29

Mysql PHP Query Runs Perfectly, But returns as false

4 Answers4