deletep1fromPerson p1, Person p2wherep1.id>p2.idandp1.Email=p2.Email; 此答案通过测试,但是效率较低. 答案二 后续思考中发现,可以使用临时表解决SELECT与DELETE同时存在的问题,答案如下所示: DELETEFROMPersonWHEREIdIN(SELECTIdFROM(SELECTp1.IdasIdFROMPerson p1, Person p2WHEREp1.Email=p2.EmailANDp1...
Duplicate rows commonly occur in MySQL databases with large numbers of entries due to errors in data processing, synchronization, and table import. If not removed, duplicates can create integrity and accuracy issues. This guide will show you how to remove duplicate rows in MySQL. Prerequisites MySQ...
如若你也不知道怎么操作后,突然对表进行增删查改的操作后,出现此问题,那么采用暴力解决法 方案一: 1、查询是否锁表 show OPEN TABLES where In_use >0; 2、在mysql黑框中或者navicat查询界面中输入: sh ... 数据库 mysql javascript 杀死进程 增删查改 mysql Deadlock found when trying to get lock 解锁...
删除重复的地址,保留ID最小的 MySQL(714ms): DELETEFROMPersonWHEREIdNOTIN(SELECT*FROM(SELECTMIN(Id)FROMPersonGROUPBYEmail )ASMid );
196. Delete Duplicate Emails Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id. +---+---+ | Id | Email | +---+---+ | 1 | john@example.com | | 2 | bob@example...
when MAC address of existing NIC interface changes, the entry in host details can get duplicated when trying to save any changes to the host details, it fails with error message: Some of the interfaces are invalid. Please check the table below. ...
mysql > delete from t where a=3 and b=3 ; mysql > insert into t(a,b,c) values(3,3,5); T2 sess2 mysql > insert into t(a,b,c) values(3,2,6); T3 sess3 mysql > insert into t(a,b,c) values(3,4,5); 其中sess2 sess3 等待申请lock_mode X locks gap before rec insert...
avoid insertion of duplicate entries in a BULK INSERT statement Bad performance of EXCEPT operator Basic - select with fixed values - invert columns to rows Basic CTE query, get full path of something recursive BCP Error - Copy direction must be either 'in', 'out' or 'format'. BCP Export...
mysql tables in use 1, locked 1 5 lock struct(s), heap size 1184, 4 row lock(s), undo log entries 2 MySQL thread id 3525490, OS thread handle 0x7f78eab82700, query id 780039714 localhost root update insert into ty(a,b) values(2,10) ...
Status:DuplicateImpact on me: None Category:MySQL Server: InnoDB Plugin storage engineSeverity:S3 (Non-critical) Version:5.1.47, 4.1, 5.0, 5.1, 5.6.99 bzrOS:Any Assigned to:Assigned AccountCPU Architecture:Any Tags:deleted,lock,purge,rows ...