如何删除mysql表中的重复值 [英] how to delete duplicate values in mysql table

问题描述

我在mysql表(my_sale_time)中的列类型为timestamp ....影响行值看起来像这样

I have column in mysql table (my_sale_time) of type timestamp....infact the rows value look like this

2010-12-01 14:38:07
2010-12-01 17:14:18
...

所以我需要mysql查询删除那些在表中多次重复的日期的值....正如我在示例sale_time_value ...... only date 中提到的那样值相同，但时间不同....所以我要获取所有行，将日期重复多次，并删除重复的日期

so what i need mysql query to delete those value whose date is repeated multiple times in table.....as i mentioned in sample sale_time_value.....only date is repeated with same value but time is different....so i want to get all rows, date is repeated multiple times and delete duplicate dates

推荐答案

删除重复行的基本原理:

The basic principle of deleting duplicate rows:

CREATE TEMPORARY TABLE tmptbl AS SELECT DISTINCT * FROM my_sale_time;
DELETE FROM my_sale_time;
INSERT INTO my_sale_time SELECT * FROM tmptbl;

您可能必须指定列和WHERE子句(我不太了解您的条件). 当然，您应该在开发服务器上对其进行测试运行，并且不要忘记将其作为具有锁定表的单个事务来运行.

You may have to specify columns and WHERE clauses (I didn't really understand your criteria). And of course you should test-run it on a development server and don't forget to run it as a single transaction with locked tables.

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