Integer values in dynamic PDO query [duplicate] - php

Question

This question already has answers here:
How to apply bindValue method in LIMIT clause?
(11 answers)
Closed 6 years ago.
I'm trying to use a dynamic PDO query (add where clause to the query if the variable is true) but i have a problem with integers values, this is my code:
$params = array();
$cond = array();
$query = "SELECT value FROM `table`";
if (!empty($firstname)) {
$cond[] = "firstname = :fn";
$params[':fn'] = $firstname;
}
if (!empty($lastname)) {
$cond[] = "lastname = :ln";
$params[':ln'] = $lastname;
}
if (count($cond)) {
$query .= ' WHERE ' . implode(' AND ', $cond);
}
$query .= " LIMIT :min, :max";
$params[':min'] = $min; // INTEGER VALUE
$params[':max'] = $max; // INTEGER VALUE
$stmt = $db->prepare($query);
$stmt->execute($params);
The problem is that PDOStatement::execute treated all values as PDO::PARAM_STR and LIMIT need integer values.
I tried with PDOStatement::bindValue using PDO::PARAM_INT parameter but i don't know how to use it in a dynamic query.

Answer 1

You already have an array of keys and values to bind in $params, so after you prepare the statement, loop through it and bind accordingly:
$params = array();
$cond = array();
$query = "SELECT value FROM `table`";
if (!empty($firstname)) {
$cond[] = "firstname = :fn";
$params[':fn'] = $firstname;
}
if (!empty($lastname)) {
$cond[] = "lastname = :ln";
$params[':ln'] = $lastname;
}
if (count($cond)) {
$query .= ' WHERE ' . implode(' AND ', $cond);
}
$query .= " LIMIT :min, :max";
$params[':min'] = $min; // INTEGER VALUE
$params[':max'] = $max; // INTEGER VALUE
$stmt = $db->prepare($query);
foreach($params as $key => $value)
{
if(is_int($value))
{
$stmt->bindValue($key, $value, PDO::PARAM_INT);
}
else
{
$stmt->bindValue($key, $value, PDO::PARAM_STR);
}
}
$stmt->execute($params);
Notice, that you must use bindValue, since bindParam will not work. The PHP manual states why:
Unlike PDOStatement::bindValue(), the variable is bound as a reference and will only be evaluated at the time that PDOStatement::execute() is called.
And once a foreach iteration is passed, $value no longer exists and can't be used as a reference. This is precisely the reason you must use bindValue

Answer 2

You can bind the Value with the optional 3rd Parameter on bindParam
Like this:
$stmt->bindParam($key, $value, PDO::PARAM_INT);
If that not work try
$stmt->bindParam($key, intval($value), PDO::PARAM_INT);
This works fine for me:
foreach($params as $key => &$value)
$stmt->bindValue($key, $value, get_type($value));
Here is my get_type() function:
function get_type($value) {
switch(true) {
case is_null($value):
return PDO::PARAM_NULL;
case is_int($value):
return PDO::PARAM_INT;
case is_bool($value):
return PDO::PARAM_BOOL;
default:
return PDO::PARAM_STR;
}
}
I'm sure there are better ways to solve this, but hey it works
(Better use PDO::bindValue() than PDO::bindParam())