mysql - MySQL:在某些条件下更新表
问题描述
我有 2 个表,主表和当前表(刷新非常小时)。两个表都具有相同的结构:
校验 | 描述 |状态 | 日期
如果出现以下情况,我需要更新/追加(添加新行)到主表中:
1) 具有新 ID 的行或
2)如果特定变量(在这种情况下为“状态”)已更改。我尝试在下面使用但没有成功:
INSERT into AGILE_TICKETS_DLY
SELECT * FROM CURR_AGILE_TICKETS curr
WHERE EXISTS (SELECT * FROM AGILE_TICKETS_DLY mstr
WHERE (curr.chk != mstr.chk) OR ( curr.chk = mstr.chk and
mstr.state != curr.state))
关于如何实现这一目标的任何指示?
解决方案
您可以尝试这对查询:
-- insert new rows
insert into agile_tickets_dly
select * from curr_agile_tickets
where chk not in (select chk from agile_tickets_dly);
-- update updated rows
update agile_tickets_dly x
join
(
select b.chk chk,b.description description,b.state state,b.date date
from agile_tickets_dly a, curr_agile_tickets b
where
a.chk=b.chk and
(a.description != b.description or a.state != b.state or a.date != b.date)
) y
on x.chk=y.chk
set x.description = y.description, x.state= y.state, x.date = y.date;
插图:
select * from agile_tickets_dly;
+------+-------------+---------+------------+
| chk | description | state | date |
+------+-------------+---------+------------+
| 0 | desc-0 | state-1 | 01-01-2017 |
| 1 | desc-1 | state-1 | 01-01-2018 |
| 2 | desc-2 | state-2 | 01-02-2018 |
| 3 | desc-3 | state-3 | 01-03-2018 |
+------+-------------+---------+------------+
-- one new row with chk=4, three updated rows with chk=1,2,3
select * from curr_agile_tickets;
+------+----------------+-----------------+----------------+
| chk | description | state | date |
+------+----------------+-----------------+----------------+
| 0 | desc-0 | state-1 | 01-01-2017 |
| 1 | desc-1 | state-1 | date-1-updated |
| 2 | desc-2-updated | state-2 | 01-02-2018 |
| 3 | desc-3 | state-3-updated | 01-03-2018 |
| 4 | desc-4 | state-4 | 01-04-2018 |
+------+----------------+-----------------+----------------+
-- after executing the two queries
select * from agile_tickets_dly;
+------+----------------+-----------------+----------------+
| chk | description | state | date |
+------+----------------+-----------------+----------------+
| 0 | desc-0 | state-1 | 01-01-2017 |
| 1 | desc-1 | state-1 | date-1-updated |
| 2 | desc-2-updated | state-2 | 01-02-2018 |
| 3 | desc-3 | state-3-updated | 01-03-2018 |
| 4 | desc-4 | state-4 | 01-04-2018 |
+------+----------------+-----------------+----------------+