Question

I am trying to decipher a particular statement that is in PHP program that is doing a Mysql query. The query has ?: and ? in it. What is there function?

$data = db_get_field("SELECT data FROM ?:order_data WHERE order_id = ?i AND type = 'A'", $order_id);

Thanks for any help.

Chris

Answer 1

They look like placeholders for prepared statements. You provide the ? where you will later provide an actual value. Consider this example from the PHP documentation:

$stmt = $dbh->prepare("INSERT INTO REGISTRY (name, value) VALUES (?, ?)");
$stmt->bindParam(1, $name);
$stmt->bindParam(2, $value);

Source: http://php.net/manual/en/pdo.prepared-statements.php

Your particular example appears to be from CS-Cart. For instance, according to their documentation ?i forces the value passed into that placeholder to be converted to an integer (this is similar to the way sprintf works).

$number = 9;
echo sprintf( "I have %d tasks.", $number );
// Outputs "I have 9 tasks."

In the above case, $number is treated as an integer. If I tried to pass a string into that slot, I’d get very different results:

$number = "completed";
echo sprintf( "I have %d tasks.", $number );
// Outputs "I have 0 tasks."

Note here how my types didn’t match up, and therefore 0 replaced completed in the output.

Bottom line, these are placeholders.