mysql 让空值用0补充的函数IFNULL(a,0)
记录，防止遗忘！sql如下：
SELECT IFNULL((SELECT sum(EO_using_value) FROM cq_energy_other as eo WHERE eo.EO_type = #{energyType} and DATE_FORMAT(EO_alt,"%Y-%m-%d") = curdate()),0) as vals;
声明：该文观点仅代表作者本人，牛骨文系教育信息发布平台，牛骨文仅提供信息存储空间服务。
记录，防止遗忘！sql如下：
SELECT IFNULL((SELECT sum(EO_using_value) FROM cq_energy_other as eo WHERE eo.EO_type = #{energyType} and DATE_FORMAT(EO_alt,"%Y-%m-%d") = curdate()),0) as vals;
