如何使用 join 和 where 子句从表中删除？ [复制]

Question

以下是我目前的代码，选择查询是我想从事件表中删除的内容。

declare @maxsnapevent table (sita varchar(10), snap date)
insert into @maxsnapevent
select sita, max(snapshot_date) from ukrmc.dbo.strategy group by sita  
--select * from @maxsnapevent 


--need to delete everything that the following code gives  
select events.sita, events.date, events.event from ukrmc.dbo.events events
join @maxsnapevent max on max.sita = events.sita  
where date >= max.snap and events.sita != 'lcypd' and events.sita != 'lonza' 

来自策略表的示例数据：

date          sita    Event              Snapshot_date
2018-01-01   London   Bank Holiday       2017-12-31 
2018-01-02   London                      2017-12-31 
2018-01-03   London                      2017-12-31
2018-01-04   London   Concert            2017-12-31
2018-01-02   London                      2018-01-01
2018-01-03   London                      2018-01-01
2018-01-04   London   Concert            2018-01-01
2018-01-01   Bham   Bank Holiday         2017-12-31 
2018-01-02   Bham                        2017-12-31 
2018-01-03   Bham                        2017-12-31
2018-01-04   Bham                        2017-12-31
2018-01-02   Bham                        2018-01-01
2018-01-03   Bham     Charity            2018-01-01
2018-01-04   Bham                        2018-01-01

事件表中的示例数据：

date         sita    Event
2018-01-01   London  Bank Holiday
2018-01-02   London  
2018-01-03   London  
2018-01-04   London  Concert
2018-01-01   Bham    Bank Holiday
2018-01-02   Bham  
2018-01-03   Bham  
2018-01-04   Bham    Concert

如您所见，每个快照都有多个站点和多个日期。

Answer 1

您是否尝试过下一个代码？

delete events
from ukrmc.dbo.events events
join @maxsnapevent max on max.sita = events.sita  
where date >= max.snap and events.sita != 'lcypd' and events.sita != 'lonza'