IFOBJECT_ID('dbo.Scores','U')ISNOTNULLDROPTABLEdbo.Scores; 临时表 IFOBJECT_ID('tempdb.dbo.#T','U')ISNOTNULLDROPTABLE#T; SQL Server 2016 新加功能 DROPTABLEIFEXISTSdbo.Scores
)--做个备份select*intoxiutaoX200a2fromxiutaoX200a--批量处理重复数据--select * from xiutaoX200a--测试案例,给表插入数据--select * from xiutaoX200a--判断临时表是否存在 如果存在则删除临时表ifexists(select1fromtempdb..sysobjectswhereid=object_id('tempdb..#t_m'))begindroptable#t_m--删除临时...
1、DROP命令: 语法: drop table 数据表 --删除整张表(包括表结构定义),速度最快,最彻底,没有保存具体日志(删除内容和定义,释放空间。就是把整个表去掉.),基本上无法恢复 1. 2、TRUNCATE命令: 语法: truncate table 数据表 --删除整张表内容(只删除数据,保留表结构),没有保存具体删除日志,会截断数据并释放...
if exists(select * from sysobjects where name='CourseCategory') drop table CourseCategory go create table CourseCategory ( CategoryId int identity(10,1) primary key, CategoryName varchar(20) not null ) go --课程表 if exists(select * from sysobjects where name='Course') drop table Course go...
IF OBJECT_ID (N'db2.schema.table1', N'U') IS NOT NULL SELECT 1 AS res ELSE SELECT 0 AS res; SQL SERVER 2016 Edit: Starting with 2016, Microsoft simplified the ability to check for non-existent objects prior to dropping, by adding the if exists keywords to drop statements. For exa...
I didn't find any easy way to "translate" the following T-SQL query in Snowflake. ALTER TABLE table1 DROP COLUMN if exists [col1] Any ideas? Thanks! t-sql snowflake-cloud-data-platform Share Follow asked Jul 6, 2020 at 12:58 Stifter 4111 silver badge66 bronze badges Add a com...
DROPTABLEIFEXISTSstudent_info_1;CREATETABLEstudent_info_1(student_idINT(8),student_nameVARCHAR(8))ENGINE=InnoDBDEFAULTCHARSET=utf8;INSERTINTOstudent_info_1(student_id,student_name)VALUE(1,'李明'),(2,'王猛'),(3,'吴丽丽'),(4,'张飞'),(5,'赵涛');DROPTABLEIFEXISTSstudent_info_2;CREATETABL...
SELECT @sql = 'EXEC ' + @SourceDB + '..SP_EXECUTESQL N''INSERT #SpaceUsed EXEC SP_SPACEUSED [' + @tableName + ']''' EXEC (@sql) end SELECT * FROM #SpaceUsed DROP TABLE #tables DROP TABLE #SpaceUsed GO /*-- 請修改資料庫名稱 EXEC DisplayDatabaseSpaceUsed N'中文資料庫名稱' EXEC...
-- 建表语句:DROPTABLEIFEXISTSactive_learning;CREATETABLEactive_learning(user_idVARCHAR(8),study_dateDATE)ENGINE=InnoDBDEFAULTCHARSET=utf8;INSERTINTOactive_learning(user_id,study_date)VALUE('u001','2021-04-01'),('u002','2021-04-01'),('u003','2021-04-03'),('u001','2021-04-06'),(...
IF EXISTS(SELECT name FROM sysobjects WHERE type=‘U’and name='Employees’) DROP table employees /*首先在系统表中查看EmployeeS表是否存在,若存在,删除该表 CREATE TABLE Employees ( EmployeelD ID_type, /*定义字段EmployeelD的类型为ID_type