DROP TABLE [IF EXISTS] [db_name.]table_name; 说明:SQL中加[IF EXISTS] ,可以防止因表不存在而导致执行报错。 参数:db_name:Database名称。如果未指定,将选择当前database。table_name:需要删除的Table名称。 3、示例 以下示例演示DROP命令的使用,依次执行如下SQL语句: --删除整个表course DROP TABLE IF EX...
SQLServer —— EXISTS子查询 2019-12-12 22:39 −一、删除数据库 use master go if exists (select * from sysdatabases where name = 'Demo') drop database Demo go 二、删除表 use PhoneList go if exists (sel... 徐林俊 0 2888 sqlserver 2012 中的 sysobjects ...
WHILE(exists (select 1 from @tablename)) BEGIN set @name=(select top 1 tablename from @tablename order by xorder desc ); SELECT @sql= 'delete from '+tablename+CHAR(13) FROM @tablename WHERE tablename=@name; select @sql; EXEC sp_ExecuteSQL @sql; IF @@Error <> 0 GOTO ErrM del...
In SQL Server, truncating a table is a fast way to clear out records from a table if you don't need to worry about rolling back. When a table is truncated, the row deletions are not logged which is why rolling back is not possible without a transaction (NOTE: you can rollback a tr...
Sql - Drop all tables in a Redshift schema, In addition to demircioglu's answer, I had to add Commit after every drop statement to drop all tables in my schema. SELECT 'DROP TABLE IF EXISTS ' || tablename || ' CASCADE; COMMIT;' FROM pg_tables WHERE schemaname = '<your_schema>'...
If Exists(Select 1 From Sys.objects where TYPE = 'U' And name = 'PAOverridesSTG') Truncate Table PAOverridesSTG Else Begin Create Table PAOverridesSTG( OverrideID Int Identity(1,1) Not Null, PAKey Int Not Null, JobKey Int Not Null, ...
If exists( SELECT * FROM information_schema.columns WHERE COLUMNPROPERTY(OBJECT_ID( QUOTENAME(table_schema)+'.'+QUOTENAME(@tableName)), column_name,'IsIdentity')=1 ) DBCC CHECKIDENT (@tableName, RESEED, 1)EndSet NoCount Off quote: Originally posted by madhivananToday I read this Article...
droptabletable_name;droptableifexiststable_name; 注意: drop会删除整个表,包括表结构和数据,释放空间 立即执行,执行速度最快 不可回滚 1.3 删除/清空表数据:delete sql命令 代码语言:sql 复制 #删除部分数据deletefromtb_namewhereclause;#清空表,仅删除数据、保留表结构,同时也不释放表空间deletefromtb_name; ...
If EXISTs (select object_name(constid) from sysforeignkeys where object_name(constid) = @ConstraintName) exec (@sqlcmd) fetch next from drop_constraints into @ConstraintName ,@MasterTable ,@MasterColumn ,@ChildTable ,@ChildColumn ,@FKOrder ...
--删除 employees 表DROPTABLEemployees;--删除 employees 表(如果存在)DROPTABLEIFEXISTSemployees; 1. 2. 3. 4. 5. 特点: 删除整个表结构,包括所有数据、索引、触发器、约束等。 操作不可逆,无法回滚。 速度非常快。 不会激活触发器。 TRUNCATE 语句 ...