原标题:TP5 数据查询一对多计算总和SUM
TP5查询语句
(1)查询语句
Db::table('student')
->alias('st')
->join(['fraction' => 'ft'], 'st.studentID=ft.studentID', 'left')
->field('st.studentID,st.studentName,ifnull(sum(ft.fraction),0) as allFraction')
->group('st.studentID')
->select()
(2)生成的sql语句
SELECT
st.studentID,
st.studentName,
ifnull( sum( ft.fraction ), 0 ) AS allFraction
FROM
`student` `st`
LEFT JOIN `fraction` `ft` ON `st`.`studentID` = `ft`.`studentID`
GROUP BY
`st`.`studentID`
执行结果