Question

我的要求可以通过以下MySQL MySQL DB中的SQL进行降级：

CREATE TABLE `test` (
  `tran_date` datetime DEFAULT NULL,
  `qty1` int(11) DEFAULT '0',
  `qty2` int(11) DEFAULT '0'
) ;

insert into test values('2019-01-01 10:00:00',1,0);
insert into test values('2019-01-01 10:00:01',2,0);
insert into test values('2019-01-01 10:00:03',0,1);
insert into test values('2019-01-01 10:00:04',0,2);
insert into test values('2019-01-01 10:00:05',1,0);
insert into test values('2019-01-01 10:00:05',3,0);
insert into test values('2019-01-01 10:00:06',0,4);
insert into test values('2019-01-01 10:00:07',0,1);

select tran_date, qty1, qty2, case when qty1=0 then (@total := @total + qty2 ) when qty1<=@total then (@total := @total - qty1)
else  ( @total := 0 ) end  as  qty3
from test , (select @total := 0 ) as T1
order by tran_date;

+---------------------+------+------+------+
| tran_date           | qty1 | qty2 | qty3 |
+---------------------+------+------+------+
| 2019-01-01 10:00:00 |    1 |    0 |    0 |
| 2019-01-01 10:00:01 |    2 |    0 |    0 |
| 2019-01-01 10:00:03 |    0 |    1 |    1 |
| 2019-01-01 10:00:04 |    0 |    2 |    3 |
| 2019-01-01 10:00:05 |    1 |    0 |    2 |
| 2019-01-01 10:00:05 |    3 |    0 |    0 |
| 2019-01-01 10:00:06 |    0 |    4 |    4 |
| 2019-01-01 10:00:07 |    0 |    1 |    5 |
+---------------------+------+------+------+

我想要的是qty3列，应该根据上一行中的值以及同一行中qty1和qty2的值进行计算。对于第一行，其值始终为0。规则是：

1. if qty1=0, the qty3 = ${qty3_in_previous_row_value} + qty2

2. if qty1 <= ${qty3_in_previous_row_value}, the qty3 = ${qty3_in_previous_row_value} - qty1

3. else, qty3 = 0

以上SQL可以在MySQL DB中工作，我想在Oracle DB中找到一个执行相同功能的SQL。非常感谢您的帮助！

Answer 1

您可以对类似于MySQL解决方案的问题使用递归查询：

ng-template

根据上一行中的列值和同一行中的其他列计算列值（Oracle 11g db）

1 个答案: