TWeightMapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.wise.sc.acquisition.business.mapper.TWeightMapper">


    <!-- 根据条件求和某字段 -->
    <select id="getSumByCondition" resultType="Double">
        SELECT
        sum(${condition})
        FROM T_Weight a
        <where>
            ${ew.sqlSegment}
        </where>
    </select>

</mapper>