I'm learning the ropes with PDO.
Here is my sql (the number of parameters that can appear in the WHERE is variable).
SELECT
ID, title
FROM
table
WHERE
something = ?
ORDER BY
:sort :dir
LIMIT
:start, :results
Here is my code:
$query = $conn->prepare($sql);
if ($parameters) {
$i = 0;
foreach ($parameters AS $parameter) {
$i++;
$query->bindParam($i, $parameter);
}
}
$query->bindParam(':start', $pagination['start'], PDO::PARAM_INT);
$query->bindParam(':results', $pagination['results'], PDO::PARAM_INT);
$query->bindParam(':sort', $pagination['sort']);
$query->bindParam(':dir', $pagination['dir']);
$query->execute();
... and here is the exception that it generates:
Invalid parameter number: mixed named and positional parameters
Is it impossible to combine positional and named parameters in the same query? Or am I missing something?
Thanks!
In layman's terms, PDO prepared statements work like this: Prepare an SQL query with empty values as placeholders with either a question mark or a variable name with a colon preceding it for each value. Bind values or variables to the placeholders. Execute query simultaneously.
PDO::query() prepares and executes an SQL statement in a single function call, returning the statement as a PDOStatement object.
Parameter binding is essential for protecting your web application from SQL-injection. Pretty much all data which is going to be used in SQL statement needs binding. Binding simply saying is just a way to tell engine that a particular piece of data is a string, number, character and so on.
Prepared statements reduce parsing time as the preparation on the query is done only once (although the statement is executed multiple times) Bound parameters minimize bandwidth to the server as you need send only the parameters each time, and not the whole query.
Yes, it's impossible.
PDO.prepare
You cannot use both named and question mark parameter markers within the same SQL statement; pick one or the other parameter style.
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