本文将详细讨论两种常见的 SQL 语句——INSERT ... ON DUPLICATE KEY UPDATE和UPDATE ... WHERE id IN (...)的执行过程、加锁顺序,以及背后的设计原理。 1.INSERT ... ON DUPLICATE KEY UPDATE的执行顺序 INSERT ... ON DUPLICATE KEY UPDATE语句允许在插入数据时处理唯一键冲突,通过更新已存在的行来避免插...
Assume that you use In-Memory OLTP in Microsoft SQL Server 2016. When you use theALTER TABLE,ADD CONSTRAINT, orPRIMARY KEYstatement to add a primary key for a memory-optimized table, even if the table already contains...
DUPLICATE KEY UPDATE batch执行时出死锁错误背景知识一、 mysql insert 与 duplicate key:典型的插入语句:多条:INSERT INTO tablename...10) ON DUPLICATE KEY UPDATE data=data+10; UPDATE t...
1、首先创建表t,其中id是自增主键,c是唯一索引 2、表中有数据如下代码所示 3、使用insert into ... on duplicate key ...语法插入记录 代码语言:javascript 代码运行次数:0 mysql>show create table t\G***1.row***Table:t Create Table:CREATETABLE`t`(`id`int(11)NOTNULLAUTO_INCREMENT,`c`int(11)...
SORT_IN_TEMPDB=OFF, IGNORE_DUP_KEY=ON, DROP_EXISTING=OFF, ONLINE=OFF, ALLOW_ROW_LOCKS=ON, ALLOW_PAGE_LOCKS=ON)ON[PRIMARY]GOcreatetable#t11 (useridint,teacheridint)declare@iintset@i=1while@i<1000begininsert#t11values(@i,@i)set@i=@i+1endupdate#t11setuserid=1,teacherid=1whereuseri...
insert into test1(a,b,c) select a , b , c from test ON DUPLICATE KEY UPDATE b=b+values(b),c=c+values(c); 就会出现ERROR 1052 (23000): Column 'b' in field list is ambiguous 这是因为在上面的sql中,mysql不知道b到底是数据test 还是test1.所以就会出现上面错误。
insert into test1(a,b,c) select a , b , c from test ON DUPLICATE KEY UPDATE b=b+values(b),c=c+values(c); 就会出现ERROR 1052 (23000): Column 'b' in field list is ambiguous 这是因为在上面的sql中,mysql不知道b到底是数据test 还是test1.所以就会出现上面错误。
I have a table in SQL Server. It has a single column Primary Key. The Key is nvarchar and looks (mostly) like 'C12345' This key is autogenerated by a scalar function. Inserting records in my app is trivial, and works without a hitch. The problem:
When you compare the in-memory SYSCOMMITTABLE and the on-disk sys.syscommittab file in Microsoft SQL Server, you may see duplicate key rows. These duplicate values may cause backup and checkpoint operations to fail. "Cannot insert duplicate key row in object 'sys.syscommittab' with unique ...
昨天评审代码时,一群大佬看到有同事的代码里使用了mysql的on duplicate key update语法实现了对数据的save or update,说这个语法有严重的性能和其他隐患问题,必须改成先查询一次分出新增集合和修改集合,再分别进行批量新增和批量修改的方式进行,并对批量修改时使用...