sql 语句删除主键、更改主键、删除重复列（多列组合）
浏览数：34 /
时间：2015年06月12日
--alter table HistoryData drop constraint PK_HistoryData
alter table HistoryData add constraint PK_HistoryData primary key (CollectionTime,Code)
更改主键
delete from HistoryData where CollectionTime between‘2014-09-01 00:00:00‘ and ‘2014-11-01 00:00:00‘and ID not in (
select id from (
select Code,CollectionTime,max(ID) id from HistoryData
where CollectionTime between‘2014-09-01 00:00:00‘ and ‘2014-11-01 00:00:00‘group by Code,CollectionTime) a)
删除重复的列。
alter table HistoryData add constraint PK_HistoryData primary key (CollectionTime,Code)
更改主键
delete from HistoryData where CollectionTime between‘2014-09-01 00:00:00‘ and ‘2014-11-01 00:00:00‘and ID not in (
select id from (
select Code,CollectionTime,max(ID) id from HistoryData
where CollectionTime between‘2014-09-01 00:00:00‘ and ‘2014-11-01 00:00:00‘group by Code,CollectionTime) a)
删除重复的列。
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