SELECTDISTINCT*INTOduplicate_tableFROMoriginal_tableGROUPBYkey_valueHAVINGCOUNT(key_value) >1DELETEoriginal_tableWHEREkey_valueIN(SELECTkey_valueFROMduplicate_table)INSERToriginal_tableSELECT*FROMduplicate_tableDROPTABLEduplicate_table 此脚本按给定顺序执行以下操作: ...
How to Delete the Duplicate Rows Delete key1by Büşra ÖZCOŞKUNCC BY-SA 4.0 Now you've identified the copies, you often want to delete the extra rows. For simplicity, I'm going to assume that either the rows are exact copies or you don't care which you remove. If there is on...
Let’s check which rows got deleted. select * from customers2 go Scenario 2.b: Delete all duplicate records but keep the first original one Let’s first truncate the customers2 table and add the same rows again. Truncate Table customers2 go Insert into customers2 Values(1, 'John', 'Pari...
AI代码解释 mysql>create tablet(id int,v int)engine=innodb;QueryOK,0rowsaffected(0.00sec)mysql>
当SQL 对 SELECT 语句进行求值时,根据满足 SELECT 语句的搜索条件的行数,可能有几行符合结果表中的条件。 结果表中的某些行可能重复。 您可以使用 DISTINCT 关键字指定不需要任何重复项,后跟表达式列表: SELECT DISTINCTJOB, SEX ... DISTINCT 表示您只想选择唯一行。 如果所选行与结果表中的另一行重复,那么将忽...
Generally, it’s best practice to put unique constraints on a table to prevent duplicate rows. However, you may find yourself working with a database where duplicate rows have been created through human error, a bug in your application, or uncleaned data from external sources. This tutorial ...
duplicate key value violates unique constraint DETAIL: xxx already exists. 处理主键重复的数据。 若是INSERT语法报错 ,可以改写成insert into xx on conflict的语法,实现主键去重,详情请参见INSERT ON CONFLICT(UPSERT)。 若是insert into xx on conflict语法报错,为数据源有重复数据导致,解决方法请参见INSERT ON...
Recursive common table expression (CTE) allows duplicate column names.Recursive CTE doesn't allow duplicate column names. Disabled triggers are enabled if the triggers are altered.Altering a trigger doesn't change the state (enabled or disabled) of the trigger. ...
Find the Bad Row: Arithmetic overflow error converting real to data type numeric. Find the date of the nearest Monday to a given date Find the difference between 2 consecutive rows in a sql table find the range between two decimal numbers Finding duplicate values for a set of columns in a...
In this post we look at ways to remove all duplicate rows except one in an SQL database. For all examples in this article, we'll be using the following MySQL "user" table: +---+---+ | id | name | +