语句为 select a.charge_person,a.charge_money,a.time_insert,b.time_insert,sum(b.moneys),(a.charge_money-sum(b.moneys))balance from (advcharge a) left join (basic b) on (a.charge_person=b.contact) where (b.time_insert>a.time_insert) group by chagre_person;
在mysql中可以运行
但是在PHP中用
 $result = $conn->query("select a.charge_person,a.charge_money,sum(b.moneys),(a.charge_money-sum(b.moneys))balance,a.time_insert from advcharge a left join basic b on a.charge_person=b.contact ;");
运行时没有结果 去掉where 子句 和group by 子句 才能运行