, $meta_value );
			}
		}

		return $sql_clauses;
	}

	/**
	 * Returns logic operator for WHERE subclause based on 'match' query argument.
	 *
	 * @param array $query_args Parameters supplied by the user.
	 * @return string
	 */
	protected function get_match_operator( $query_args ) {
		$operator = 'AND';

		if ( ! isset( $query_args['match'] ) ) {
			return $operator;
		}

		if ( 'all' === strtolower( $query_args['match'] ) ) {
			$operator = 'AND';
		} elseif ( 'any' === strtolower( $query_args['match'] ) ) {
			$operator = 'OR';
		}
		return $operator;
	}

	/**
	 * Returns filtered comma separated ids, based on query arguments from the user.
	 *
	 * @param array  $query_args Parameters supplied by the user.
	 * @param string $field      Query field to filter.
	 * @param string $separator  Field separator.
	 * @return string
	 */
	protected function get_filtered_ids( $query_args, $field, $separator = ',' ) {
		$ids_str = '';
		$ids     = isset( $query_args[ $field ] ) && is_array( $query_args[ $field ] ) ? $query_args[ $field ] : array();

		/**
		 * Filter the IDs before retrieving report data.
		 *
		 * Allows filtering of the objects included or excluded from reports.
		 *
		 * @param array  $ids        List of object Ids.
		 * @param array  $query_args The original arguments for the request.
		 * @param string $field      The object type.
		 * @param string $context    The data store context.
		 */
		$ids = apply_filters( 'woocommerce_analytics_' . $field, $ids, $query_args, $field, $this->context );

		if ( ! empty( $ids ) ) {
			$ids_str = implode( $separator, $ids );
		}
		return $ids_str;
	}

	/**
	 * Assign report columns once full table name has been assigned.
	 */
	protected function assign_report_columns() {}
}