fengda 发表于 2016-10-25 05:56:43

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;
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