protected function sql_where() {

		global $wpdb;

		$sql = 'WHERE 1';

		// "IN" clauses for id fields.
		$ids_include = array(
			'actor'   => 'actor_id',
			'object'  => 'object_id',
			'include' => 'id',
		);
		foreach ( $ids_include as $query_key => $db_key ) {
			$ids = $this->get( $query_key );
			if ( $ids ) {
				$prepared = implode( ',', $ids );
				$sql     .= " AND {$db_key} IN ({$prepared})";
			}
		}

		// "NOT IN" clauses for id fields.
		$ids_exclude = array(
			'actor_not_in'  => 'actor_id',
			'object_not_in' => 'object_id',
			'exclude'       => 'id',
		);
		foreach ( $ids_exclude as $query_key => $db_key ) {
			$ids = $this->get( $query_key );
			if ( $ids ) {
				$prepared = implode( ',', $ids );
				$sql     .= " AND {$db_key} NOT IN ({$prepared})";
			}
		}

		// Matching fields.
		$matching = array( 'object_type', 'event_type', 'event_action' );
		foreach ( $matching as $key ) {
			$val = $this->get( $key );
			if ( $val ) {
				$sql .= sprintf( " AND {$key} = '%s'", esc_sql( $val ) );
			}
		}

		// Date fields.
		$before = $this->get( 'date_before' );
		if ( $before ) {
			$sql .= $wpdb->prepare( ' AND date < %s', $before );
		}

		$after = $this->get( 'date_after' );
		if ( $after ) {
			$sql .= $wpdb->prepare( ' AND date > %s', $after );
		}

		if ( $this->get( 'suppress_filters' ) ) {
			return $sql;
		}

		/**
		 * Filters the query WHERE clause
		 *
		 * @since 3.36.0
		 *
		 * @param string            $sql          The WHERE clause of the query.
		 * @param LLMS_Events_Query $events_query Instance of LLMS_Events_Query.
		 */
		return apply_filters( 'llms_events_query_where', $sql, $this );

	}