Using array variable in SQL select statement returns "Array to string conversion"

Question

I'm trying to make a compound statement where it will select threads where the 'node_id' column is in an array of values set in $node_ids

$node_ids = ['13', '14'];
$db = $this->app->db();
return $db->fetchAllColumn($db->limit("
        SELECT thread_id
        FROM xf_thread
        WHERE thread_id > ?
        AND node_id in " . $node_ids . "
        ORDER BY thread_id
    ", $batch
), $start);

However I get an error

Array to string conversion

on the line with:

AND node_id in " . $node_ids . "

`$node_ids` is an array. You can only concatenate strings. Use `implode()` to convert the array to a comma-delimited string. — Barmar, Sep 28 '22 at 15:18
And don't forget that you need `()` around the list: `node_id in (13, 14)` — Barmar, Sep 28 '22 at 15:18
But it would be better to use a prepared statement with parameters instead of concatenating strings. — Barmar, Sep 28 '22 at 15:19
Does this answer your question? [Reference - What does this error mean in PHP?](https://stackoverflow.com/questions/12769982/reference-what-does-this-error-mean-in-php) — user3783243, Sep 28 '22 at 15:27
Fixed by changing to this line: `AND node_id in (" . implode(',', $node_ids) . ")` — Robert Iannicca, Sep 28 '22 at 16:01
@RobertIannicca if resolved, you should consider self-answering the question by clicking the "Add an Answer" below. — James Risner, Oct 02 '22 at 15:59

score 0 · Accepted Answer · answered Oct 08 '22 at 06:37

This works based on comment by Barmar:

$node_ids = ['13', '14'];
$db = $this->app->db();
return $db->fetchAllColumn($db->limit("
        SELECT thread_id
        FROM xf_thread
        WHERE thread_id > ?
        AND node_id in (" . implode(',', $node_ids) . ")
        ORDER BY thread_id
    ", $batch
), $start);

Using array variable in SQL select statement returns "Array to string conversion"

1 Answers1