使用DROP TABLE语句来删除表。在SQL Server中,如果表存在,你可以在一个条件语句中执行此操作。对于MySQL,DROP TABLE IF EXISTS语句已经包含了检查表是否存在的逻辑。 如果不存在,不执行任何操作或给出提示信息: 在SQL Server中,你可以使用ELSE子句来打印一条消息说明表不存在。对于MySQL,如果表不存在,DROP TABLE ...
select count(*) into c from user_tables where table_name = upper('continent'); if c = 1 then execute immediate 'drop table continent'; end if; end; 这两个脚本都运行良好,但我的老板想要IF EXIT类的东西。任何人都可以帮助我。在这种情况下如何使用 IF EXIT ?
drop database [数据库名] 2 判断表是否存在 Sql代码 if exists (select * from sysobjects where id = object_id(N’[表名]’) and OBJECTPROPERTY(id, N’IsUserTable’) = 1) drop table [表名] if exists (select * from sysobjects where id = object_id(N’[表名]’) and OBJECTPROPERTY(id...
DROPMany help itemsforyour request exist.Tomake a more specific request, please type'help <item>',where<item>isoneofthe following topics:ALTERTABLEDEALLOCATEPREPAREDROPDATABASEDROPEVENTDROPFUNCTIONDROPFUNCTIONUDFDROPINDEXDROPPROCEDUREDROPRESOURCEGROUPDROPROLEDROPSERVERDROPSPATIAL REFERENCE SYSTEMDROPTABLEDROPTAB...
DROP IF EXISTS Each of the DROP statements supports an IF EXISTS clause. This allows the drop of an object to complete successfully, with no error being issued, if the object does not exist. For example, to drop the EMPLOYEE table from WORKLIB, issue the following statement:...
drop table 数据表名 ***/ use stuDB go if exists (select * from sysobjects where name = 'infos') drop table infos go 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 3.添加约束 /*** 添加约束 语法结构: alter table 数据表名 add
DROPTABLEIFEXISTS`score`;CREATETABLE`score`(`sid`int(11)NOTNULLAUTO_INCREMENT,`student_id`int(11...
2. Why Should We Check if a Table Exists Before Dropping It? The DROP TABLE clause deletes a table and all its data from the database in SQL. However, this commandthrows an error when the table doesn’t exist in the database used,disrupting the flow of the SQL script or application....
IF COL_LENGTH( '表名','列名') IS NULL PRINT 'not exists' ELSE PRINT 'exists' alter table 表名drop constraint 默认值名称 go alter table 表名drop column 列名 go --- --判断要创建临时表是否存在 If Object_Id('Tempdb.dbo.#Test') Is Not Null Begin print '存在' End Else Begin...
这是我的密码:ALTER TABLE $1 DROPCOLUMN IF EXIST $2;language 'psql'; 错误:"$$ language‘psql“处或附近的语法错误;create dropColumn( 浏览6提问于2016-01-02得票数 1 回答已采纳 2回答 PostgreSQL (9.4)临时表作用域 、、 在一些恶化之后,当一个函数调用另一个函数时,我发现(IMO)奇怪的行为。如果...