how to limit search to post titles?

Question

Is there a way to limit search to post titles? I know I can modify query.php core file but there must be a way to do it with hooks right?

Thanks in advance!

Answer 1

Here's a filter that'll do the trick. Drop it into your theme's functions.php or a plugin.

/**
 * Search SQL filter for matching against post title only.
 */
function __search_by_title_only( $search, &$wp_query )
{
    global $wpdb;

    if ( empty( $search ) )
        return $search; // skip processing - no search term in query

    $q = $wp_query->query_vars;    
    $n = ! empty( $q['exact'] ) ? '' : '%';

    $search =
    $searchand = '';

    foreach ( (array) $q['search_terms'] as $term ) {
        $term = esc_sql( like_escape( $term ) );
        $search .= "{$searchand}($wpdb->posts.post_title LIKE '{$n}{$term}{$n}')";
        $searchand = ' AND ';
    }

    if ( ! empty( $search ) ) {
        $search = " AND ({$search}) ";
        if ( ! is_user_logged_in() )
            $search .= " AND ($wpdb->posts.post_password = '') ";
    }

    return $search;
}
add_filter( 'posts_search', '__search_by_title_only', 500, 2 );

Most of the code is just copied from the WP_Query class, except with the post_content LIKE's removed.

UPDATE: This code has been updated for WordPress 3.2.1. I'm surprised it even worked before as $wpdb wasn't global!