Limit amount of results returned

Question

How can I limit the amount of results returned?

$images = $wpdb->get_col("
    SELECT ID FROM $wpdb->posts
    WHERE post_type = 'attachment'
    AND ID in ($meta)
    ORDER BY menu_order ASC
");

Answer 1

$images = $wpdb->get_col("
    SELECT ID FROM $wpdb->posts
    WHERE post_type = 'attachment'
    AND ID in ($meta)
    ORDER BY menu_order ASC
    LIMIT 5
");

Like @Kaiser suggested you can specify a range (5th to 20th results, a total of 15 results are returned at max) like this:

$images = $wpdb->get_col("
    SELECT ID FROM $wpdb->posts
    WHERE post_type = 'attachment'
    AND ID in ($meta)
    ORDER BY menu_order ASC
    LIMIT 5,20
");

Answer 2

As an addition to @Ashfame Answer: You can not only set a "hard" limit, but also a range, using LIMIT 1,100 which would bring you the results 1-100.

Answer 3

Why not just use get_posts()?

<?php
$attachments = get_posts( array(
    'post_type' => 'attachment', // post attachments
    'post_mime_type' => 'image', // only images
    'post_parent' => $post->ID,  // children of the current post
    'number_posts' => 5          // <-- THIS IS THE NUMBER OF POSTS LIMIT
) );
?>

I always prefer function calls to raw DB queries.