Executing a bad PDO query does not yield an error [duplicate] - mysql

Question

This question already has answers here:
Why does this PDO statement silently fail?
(2 answers)
Closed 5 years ago.
Here is an invalid SQL and I m expecting an error, but the PDO error seems always 00000, what did I do wrong?
<?php
run('select now()');
run('pls give me an error');
function run($sql) {
$pdo = new PDO('mysql:host=localhost;db=mydb', $user, $pass);
echo $sql . "<br>";
$sth = $pdo->prepare($sql);
$sth->execute();
$row = $sth->fetch(PDO::FETCH_ASSOC);
print_r($row);
print_r($pdo->errorInfo());
}
And here is the result:
select now()
Array
(
[now()] => 2017-10-03 02:58:09
)
Array
(
[0] => 00000
[1] =>
[2] =>
)
pls give me an error
Array
(
[0] => 00000
[1] =>
[2] =>
)
But I have another page running against the same db and get this error:
Err 1064: You have an error in your SQL syntax;
check the manual that corresponds to your MariaDB
server version for the right syntax to use near
'please give me an error' at line 1
updated
The other page is able to produce error is actually using the following:
$sth = $pdo->query($sql);
print_r($pdo->errorInfo());

Answer 1

For the syntactically or any other way incorrect prepared statements to throw you need to disable prepared statements emulation:
$pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
By default PDO is set up to emulate those, which honestly does not make much sense.
With emulated prepares disabled PDO::prepare() method creates a temporary server-side object that holds a prepared statement then executes it.
Additionally you may want to enable PDO exceptions, that way it's harder to not handle unexpected query failures:
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
References:
http://php.net/manual/en/pdo.setattribute.php

Answer 2

I've no idea why errorInfo() sometimes doesn't work but I confirm he behavior.
Given that setting error mode to exceptions always works and given that exceptions are much more useful than manual error checking, this function is useless anyway.
So, change your function this way
function run($pdo, $sql, $params = null) {
$sth = $pdo->prepare($sql);
$sth->execute($params);
return $stmt;
}
$pdo = new PDO('mysql:host=localhost;db=mydb', $user, $pass);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
run($pdo, 'select now()');
run($pdo, 'pls give me an error');
and have your error message first class