Dynamically change column name in PDO statement [duplicate] - php

Question

This question already has an answer here:
Can I use a PDO prepared statement to bind an identifier (a table or field name) or a syntax keyword?
(1 answer)
Closed 3 years ago.
Is it possible pass a column name as parameter in a prepared MySQL statement? Take the following example:
UPDATE Images
SET :placement = :imageURL
WHERE ID = :titleID;
PDO adds ' around each parameter, so the middle line above becomes:
SET 'Homepage' = '1.jpg'
Which MySQL doesn't like. Is there a way to include parameters for fieldnames in PDO statements and have them accepted?
Otherwise I guess I'll have to write several different PDO statements, depending on what's been chosen(?).

Answer 1

You would need to do something like this:
$column = 'someColumn';
$stmt = $db->prepare("UPDATE tableName SET {$column} = :columnValue WHERE ID = :recordId");
Parameterized placeholders are only for values.
I would suggest you read the comment #YourCommonSense posted on your question.

Answer 2

In situations such as this, I use a different sort of replacement parameters, like so:
$unitLabel = 'store_number';
$sql = 'select * from users where [unitLabel] = :unit and level = :level;';
$sql = str_replace('[unitLabel]', $unitLabel, $sql);
$params = array(
':unit' => 300,
':level' => 'admin',
);
$stmt = $dbh->prepare($sql);
$stmt->execute($params);
The prepared SQL query ends up being processed (more or less) as:
SELECT * FROM USERS WHERE store_number = 300 AND level = 'admin';
Which works for my situation. I hope this helps. :)