protected function sql_where() {

		global $wpdb;

		$sql = 'WHERE 1';

		// "IN" clauses for id fields.
		$ids_include = array(
			'include' => 'id',
			'user'    => 'user_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(
			'exclude'     => 'id',
			'user_not_in' => 'user_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})";
			}
		}

		// Permission match.
		$permissions = $this->get( 'permissions' );
		if ( $permissions ) {
			$sql .= $wpdb->prepare( ' AND permissions = %s', $permissions );
		}

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

		/**
		 * Filters the query WHERE clause
		 *
		 * @since 1.0.0-beta.1
		 *
		 * @param string                   $sql             The WHERE clause of the query.
		 * @param LLMS_REST_API_Keys_Query $apy_keys__query Instance of LLMS_REST_API_Keys_Query.
		 */
		return apply_filters( 'llms_rest_api_key_query_where', $sql, $this );

	}