WordPress Admin Post search by title only

wp-search-by-title-only

<?php
// mu-plugin or included in theme/plugin

add_filter( 'posts_search', 'maybe_search_by_title_only', 10, 2 );

// add query var 'title_only' to the allowed query vars.
add_filter( 'query_vars', function ( $vars ) {
	$vars[] = 'title_only';

	return $vars;
} );

// add a checkbox to the admin post search form to search by title only.
add_action( 'restrict_manage_posts', function () {
	if ( ! is_admin() || ! current_user_can( 'edit_posts' ) ) {
		return;
	}
	// Add a checkbox to the search form.
	echo '<label for="title_only" style="margin: 0 10px; line-height: 2.5em;">';
	echo '<input type="checkbox" id="title_only" name="title_only" value="1" ' . checked( isset( $_GET['title_only'] ), true, false ) . ' />';
	echo __( 'Search by title only' );
	echo '</label>';
} );

/**
 * Modify the search query to search by title only, if the 'title_only' query var is set, and only in the admin area.
 *
 * @param string $search The search SQL.
 * @param WP_Query $wp_query The WP_Query instance.
 * @return string Modified search SQL.
 */
function maybe_search_by_title_only( $search, $wp_query ) {
	if ( ! is_admin() || empty( $search ) ) {
		return $search;
	}
	global $wpdb;
	$q = $wp_query->query_vars;
	// Detect if the search is for titles only.
	if ( empty( $q['title_only'] ) || ! (int) $q['title_only'] ) {
		return $search;
	}
	$x         = ! empty( $q['exact'] ) ? '' : '%';
	$search    = '';
	$searchand = '';

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

	return $search;
}