4张表级联查询的结果分组求和:

select sum(c.quantity) as quantity,sum(c.prefee) as feefrom  Cs_AccountBill ajoin Cs_AccountBillDetail b on a.id= b.AccountBillIdjoin Cs_SettlementDetail c on c.accountBillDetailID = b.id join Cs_Settlement d on c.settlementID = d.id

While it's about 21W records of the result，time of select is about 31 ms.

更改如下：

select c.quantity,c.prefeefrom  Cs_AccountBill ajoin Cs_AccountBillDetail b on a.id= b.AccountBillIdjoin Cs_SettlementDetail c on c.accountBillDetailID = b.id join Cs_Settlement d on c.settlementID = d.id

　　

查询时间：40ms左右

 

再将查询的结果map reduce 大概80+ms

BigDecimal sum = list.parallelStream().map(Person::getFee).reduce(BigDecimal::add).get();//勿用list.stream(),慢