MySQL避免SUM求和返回null

MySQL

SELECT
	COALESCE(SUM(money_award), 0) AS money_award
FROM
	invite_award
WHERE
	master_id = '1'

<select id="sumByMasterId" resultType="BigDecimal">
	SELECT
		COALESCE(SUM(money_award), 0) AS money_award
	FROM
		invite_award
	WHERE
		master_id = #{masterId}
</select>