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# PDOStatement::bindParam [PHP PDO Reference](#) PDOStatement::bindParam — Binds a parameter to a specified variable name (PHP 5 >= 5.1.0, PECL pdo >= 0.1.0) * * * ## Description ### Syntax bool PDOStatement::bindParam ( mixed $parameter , mixed &$variable [, int $data_type = PDO::PARAM_STR [, int $length [, mixed $driver_options ]]] ) Binds a PHP variable to a corresponding named or question mark placeholder in the SQL statement that was used to prepare the statement. Unlike PDOStatement::bindValue(), the variable is bound by reference and will only have its value evaluated at the time that PDOStatement::execute() is called. Most parameters are input parameters, that is, parameters that are used in a read-only fashion to build up the query. Some drivers support the invocation of stored procedures that return data as output parameters, and some support input/output parameters, that is, a parameter that sends data and receives an updated value back. * * * ## Parameters **parameter** Parameter identifier. For a prepared statement using named placeholders, this will be a parameter name of the form :name. For a prepared statement using question mark placeholders, this will be the 1-indexed position of the parameter. **variable** The PHP variable to bind to the SQL statement parameter. **data_type** Use PDO::PARAM_* constants to explicitly specify a parameter type. To return a value from an INOUT parameter from a stored procedure, you must use the bitwise OR operator to set the PDO::PARAM_INPUT_OUTPUT bit for the data_type parameter. **length** Allocation hint. **driverdata** The length of the data type. To indicate that the parameter is an OUT parameter from a stored procedure, you must explicitly set this length. **driver_options** * * * ## Return Values Returns TRUE on success or FALSE on failure. * * * ## Examples ### Executing a prepared statement with named placeholders prepare('SELECT name, colour, calories FROM fruit WHERE calories bindParam(':calories', $calories, PDO::PARAM_INT); $sth->bindParam(':colour', $colour, PDO::PARAM_STR, 12); $sth->execute();?> ### Executing a prepared statement with question mark placeholders prepare('SELECT name, colour, calories FROM fruit WHERE calories bindParam(1, $calories, PDO::PARAM_INT); $sth->bindParam(2, $colour, PDO::PARAM_STR, 12); $sth->execute();?> ### Calling a stored procedure with an INOUT parameter prepare('CALL puree_fruit(?)'); $sth->bindParam(1, $colour, PDO::PARAM_STR|PDO::PARAM_INPUT_OUTPUT, 12); $sth->execute();print("After pureeing fruit, the colour is: $colour");?> * * PHP PDO Reference](#)