Fix ability to sort course students table by completed date.

.changelogs/1969-sort-course-students-by-completed.yml

@@ -0,0 +1,5 @@
+significance: patch
+type: fixed
+links:
+- "#1969"
+entry: Fixed ability to sort course students table by completed date.

includes/admin/reporting/tables/llms.table.course.students.php

@@ -5,7 +5,7 @@
  * @package LifterLMS/Admin/Reporting/Tables/Classes
  *
  * @since 3.2.0
- * @version 3.18.0
+ * @version [version]
  */
 
 defined( 'ABSPATH' ) || exit;
@@ -267,12 +267,13 @@ public function get_table_search_form_placeholder() {
 	}
 
 	/**
-	 * Execute a query to retrieve results from the table
+	 * Execute a query to retrieve results from the table.
 	 *
-	 * @param    array $args  array of query args
-	 * @return   void
-	 * @since    3.15.0
-	 * @version  3.15.0
+	 * @since 3.15.0
+	 * @since [version] Add ability to sort by completion date.
+	 *
+	 * @param array $args Array of query args.
+	 * @return void
 	 */
 	public function get_results( $args = array() ) {
 
@@ -299,6 +300,15 @@ public function get_results( $args = array() ) {
 		$sort = array();
 		switch ( $this->get_orderby() ) {
 
+			case 'completed':
+				$sort = array(
+					'completed'  => $this->get_order(),
+					'last_name'  => 'ASC',
+					'first_name' => 'ASC',
+					'id'         => 'ASC',
+				);
+				break;
+
 			case 'enrolled':
 				$sort = array(
 					'date'       => $this->get_order(),

includes/class.llms.student.query.php

@@ -5,7 +5,7 @@
  * @package LifterLMS/Classes
  *
  * @since 3.4.0
- * @version 4.10.2
+ * @version [version]
  */
 
 defined( 'ABSPATH' ) || exit;
@@ -337,11 +337,12 @@ private function sql_search() {
 	}
 
 	/**
-	 * Set up the SQL for the select statement
+	 * Set up the SQL for the select statement.
 	 *
 	 * @since 3.13.0
 	 * @since 4.10.2 Drop usage of `this->get_filter( 'select' )` in favor of `'llms_student_query_select'`.
 	 *               Use `$this->sql_select_columns({columns})` to determine additional columns to select.
+	 * @since [version] Add a subquery for completed date.
 	 *
 	 * @return string
 	 */
@@ -357,6 +358,7 @@ private function sql_select() {
 
 		// All the possible fields.
 		$fields = array(
+			'completed'        => "( {$this->sql_subquery( 'updated_date', '_is_complete' )} ) AS completed",
 			'date'             => "( {$this->sql_subquery( 'updated_date' )} ) AS `date`",
 			'last_name'        => 'm_last.meta_value AS last_name',
 			'first_name'       => 'm_first.meta_value AS first_name',
@@ -417,16 +419,18 @@ private function sql_status_in( $column = 'status' ) {
 	}
 
 	/**
-	 * Generate an SQL subquery for the dynamic status or date values in the main query
+	 * Generate an SQL subquery for the dynamic status or date values in the main query.
 	 *
 	 * @since 3.13.0
+	 * @since [version] Add `$meta_key` argument.
 	 *
 	 * @param string $column Column name.
+	 * @param string $meta_key Optional meta key to use in the WHERE condition. Defaults to '_status'.
 	 * @return string
 	 */
-	private function sql_subquery( $column ) {
+	private function sql_subquery( $column, $meta_key = '_status' ) {
 
-		$and = '';
+		global $wpdb;
 
 		$post_ids = $this->get( 'post_id' );
 		if ( $post_ids ) {
@@ -436,11 +440,9 @@ private function sql_subquery( $column ) {
 			$and = "AND {$this->sql_status_in( 'meta_value' )}";
 		}
 
-		global $wpdb;
-
 		return "SELECT {$column}
 				FROM {$wpdb->prefix}lifterlms_user_postmeta
-				WHERE meta_key = '_status'
+				WHERE meta_key = '{$meta_key}'
 		  		  AND user_id = id
 		  		  {$and}
 				ORDER BY updated_date DESC