4

I am getting an array to string conversion error when I am trying to run a PDO execute. The execute has to inputs one being a normal string and the other an array. Heres my code:

$id = "1";    
$array = array("a",  "b",  "c");
$in  = str_repeat('?,', count($array) - 1) . '?';

$sql1 = "SELECT * FROM tbl1 AS tb1 RIGHT JOIN tbl2 AS tb2 ON (tb1.e_id = tb2.e_id)LEFT JOIN tbl3 AS tb3 ON (tb2.m_id = tb3.m_id) WHERE tb1.u_id = ? AND tb1.letters IN ($in)";


$statement1 = $db_handle->prepare($sql1);
$statement1->setFetchMode(PDO::FETCH_ASSOC);
$statement1->execute(array($id,$array));

$res = $statement1->fetchAll();

So the execute line gives me the string conversion error. I have printed my array and the question marks and they output fine. The sql statement is also fine, I have tried it on phpMyAdmin and it works just fine so clearly I am not using the execute properly but I am not sure how to change the way I have executed it.

Can someone explain it to me?

Improve this question
1

2 Answers 2

Reset to default
6

execute() method expects a single array. From the documentation:

Execute the prepared statement. If the prepared statement included parameter markers, you must either:

  • (snip)
  • pass an array of input-only parameter values

With array($id,$array) you'd be passing a multi-dimensional array that looks like this:

Array
(
    [0] => 1
    [1] => Array
        (
            [0] => a
            [1] => b
            [2] => c
        )

)

This is certainly not what it expects. It needs a single-dimensional array containing the values to be inserted.

To fix this issue, you have to modify the array format. Add the ID to the start of the array, like so:

$array = array(1, "a",  "b",  "c");

If the ID variable is generated dynamically, then you can manually add it to the array start using array_unshift() function:

$id = "1";    
$array = array("a",  "b",  "c");
$array = array_unshift($array, $id);

... and then modify the execute() call like so:

$statement1->execute($array);
Improve this answer
Sign up to request clarification or add additional context in comments.

1 Comment

You've misinterpreted that line. Check Example #5 on the docs page for ->execute().
1

->execute() expects you to send it an array with each element representing each ? in the query.

You are only sending it 2 elements, so it's gonna try to use the entire array as the 2nd ?, which is why it's trying to convert it to a string. And then it will probably complain about not having enough parameters.

Try it like this:

$dataArray = $array;
array_unshift($dataArray, $id);

$statement1->execute($dataArray);
Improve this answer

4 Comments

This did get rid of the string conversion error thank you but it creates a further error and gives me this error Invalid parameter number: number of bound variables does not match number of tokens is this down to the conversion or another error entirely?
@user3144542: Try to echo $sql1; to see how many ?s there are in it. Then var_dump($dataArray) and make sure the counts match.
@AmalMurali: You've misinterpreted that line. It's saying that you cannot do this: SELECT * FROM table WHERE id IN (:ids) and then try to call ->execute(array(":ids" => array(1,2,3)).
Nope the ? match but I did find a solution a user posted the answer then removed it but the answer is in the following link I had to restructure the query a little bit by doing the IN before the = but now it works as intended.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.