begin tran if exists (select * from table with (updlock,serializable) where key = @key) begin update table set ... where key = @key end else begin insert into table (key, ...) values (@key, ...) end commit tran 或者 begin tran update table with (serializable) set ... where ke...
INSERT OR UPDATE操作允许你在单个语句中执行插入或更新操作。如果记录不存在,则插入新记录;如果记录存在,则更新现有记录。SQL Server提供了多种方式来实现这一操作,包括使用MERGE语句、IF EXISTS条件和UPSERT函数(在某些情况下)。 优势 简化代码:通过单个语句完成插入和更新操作,减少了代码复杂性。 提高效率:减少了数据...
相关搜索:sql server insert or update在sql server compact edition上执行Insert OR Update(upsert)INSERT和UPDATE的执行状态- MS SQL ServerInsert/ Update过程给出无效列名错误SQL Server在SQL Server 2012中的select查询后运行update或insert查询insert with update的SQL insert触发器delete、insert或update触发器之后的...
CREATE TRIGGER tr_T_A ON T_A for INSERT,UPDATE,DELETE 如IF exists (select * from inserted) and not exists (select * from deleted) 则为 INSERT 如IF exists(select * from inserted ) and exists (select * from deleted) 则为 UPDATE 如IF exists (select * from deleted) and not exists (s...
<insert id="insertOrUpdate"> if not exists (select 1 from table_name where column_name = XX) insert into table_name(id, update_time) values(1, getdate()) else update table_name set update_time = getdate() where id = 1 </insert> ...
方案1:SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; BEGIN TRANSACTION; IF EXISTS (SELECT 1 FROM dbo.table WHERE PK = @PK) BEGIN UPDATE ... END ELSE BEGI
SQL Server2000中死锁经验总结 虽然不能完全避免死锁,但可以使死锁的数量减至最少。将死锁减至最少可以增加事务的吞吐量并减少系统开销,因为只有很少的事务: 回滚,而回滚会取消事务执行的所有工作。 由于死锁时回滚而由应用程序重新提交。 下列方法有助于最大限度地降低死锁: ...
使用并行还是串行程是MsSQL自动评估选择的。单个任务分解成多个任务,就可以在处理器上运行。例如耽搁查询的排序、连接、扫描和GROUP BY字句同时执行,SQL SERVER根据系统的负载情况决定最优的并行等级,复杂的需要消耗大量的CPU的查询最适合并行处理。但是更新操作UPDATE,INSERT,DELETE还不能并行处理。
but i'm not using my sql.it's sql server 2005!. Anonymous February 28, 2010 Just for sake of completeness 2 thingsIsnt Update a Blocking call? In case the user expect most of the time Insert will happen he should go with if exists(select) insert else update. Also in some cases only...
Is this more efficient than doing an "IF SELECT COUNT(*) FROM ... > 0 ELSE ... " That would select only one value, I'm just not fully sure of the overhead created when SQL Server executes the SELECT in this vs. an UPDATE that makes no changes. I'm not really sure how to ...