Using a variable as the column name in a mysql query

Question

I'm trying to turn this:

"SELECT username FROM $table WHERE username='$newName'"

Into this:

"SELECT $column FROM $table WHERE $column='$newName'"

But when I use or die() on it, I get an error saying that there is incorrect syntax near WHERE username='someNameHere'. What is the correct way to substitute the column name, assuming that's what's wrong?

Edit: Code is just this. The values should be correct as I don't see any mispellings in the error.

$sql = "SELECT $column FROM $table WHERE $column='$newName'";
$result = mysql_query($sql) or die( mysql_error());

Show us your code, i don't get you about 'when i use or die() on it'. — Stefan Koenen
– Stefan Koenen, Commented Jul 3, 2013 at 13:14
That should work. Are you sure your variables contain expected values? — John Conde
– John Conde, Commented Jul 3, 2013 at 13:14
Please, stop using the Deprecated mysql_* extension, switch to PDO or mysqli_*, and start using prepared statements, and make sure there are no spaces, quotes or backticks in the variables — Elias Van Ootegem
– Elias Van Ootegem, Commented Jul 3, 2013 at 13:17
@RocketHazmat Ah, thank you, it was the $table part that got overwritten some lines before this but I just kept concentrating on the $column part. — idlackage
– idlackage, Commented Jul 3, 2013 at 13:24

Jakolcz · Accepted Answer · 2013-07-03 13:22:57Z

8

Make your query like this

$sql = "SELECT ".$column." FROM ".$table." WHERE ".$column."='".$newName."'"

BTW this is SQLinjection vulnerable code. You should check the variables before using them in query. Also you should start using mysqli and prepared statements

edited Jul 3, 2013 at 13:22

answered Jul 3, 2013 at 13:17

Jakolcz

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Mahmoud Gamal · Accepted Answer · 2013-07-03 13:20:17Z

1

"SELECT ".$column." FROM ".$table." WHERE ".$column."=".$newName;

Check to see if that works for you.

edited Jul 3, 2013 at 13:20

Mahmoud Gamal

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answered Jul 3, 2013 at 13:16

PmanAce

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