如何删除MySQL中的记录并保持最新日期
问题描述：
示例table_1
ID Email Answer UpdateDate
1 xxx.@xx.com 1 2011-07-02
2 xxx.@xx.com 3 2011-07-11
3 vvv.@xx.com 3 2011-07-12
4 vvv.@xx.com 5 2011-07-13
5 xxx.@xx.com 5 2011-07-14
6 xxx.@xx.com 4 2011-07-14
7 xxx.@xx.com 4 2011-07-14
8 zzz.@xx.com 4 2011-07-15
如何删除此记录，但保留最新的UpdateDate
How do I delete this records but keep the latest UpdateDate
结果:
ID Email Answer UpdateDate
4 vvv.@xx.com 5 2011-07-13
7 xxx.@xx.com 4 2011-07-14
8 zzz.@xx.com 4 2011-07-15
答
您可以使用临时变量存储最高日期，然后使用单独的查询删除所有<比起那个来说.请记住，变量是特定于连接的.
You could use a temporary variable to store the highest date and then a seperate query to delete everything that is < than that. Remember that variables are connection specific.
select max(UpdateDate) from table_1 into @TempUpdateDate
delete from table_1 where UpdateDate < @TempUpdateDate