it returns theobject ID; otherwise, it returnsNULL. We can use theCOALESCE()function to convert this result into a boolean value. However,this approach returnstrueif any database object with that name exists in
if exists (select * from sysobjects where id = object_id(N’[存储过程名]’) and OBJECTPROPERTY(id, N’IsProcedure’) = 1) drop procedure [存储过程名] 判断临时表是否存在 if object_id(’tempdb..#临时表名’) is not null drop table #临时表名 判断视图是否存在 --SQL Server 2000 IF...
When I need to check if a table exists in PHP, I select something from that table trapping the error with '@' if it doesn't exit. For instance: $result=@mysql_query('select * from tb2check limit 1', $handle); if ($result) { // table exists mysql_free($result); } ...
if exists (select 1 from sysobjects where name = '存储过程名' and xtype = 'P') drop procedure [存储过程名] 4 判断临时表是否存在 Sql代码 if object_id('tempdb..#临时表名') is not null drop table #临时表名 5 判断视图是否存在 Sql代码 ...
SELECT TABLE_NAME FROM DBName.INFORMATION_SCHEMA.Tables WHERE TABLE_NAME='Article'How do I check this in C#?As for how you check that in C#? You just make sure the Row count returned from the query is 1. See this article I have already posted. How do I get the number of rows retur...
问sql if exists简单语法错误EN像列 LIKE 字符串或者列 BETWEEN 值 1 AND 值 2这样的谓词需要指定 2...
一般drop table if exists是数据库里面的，后面接表名，如：drop table if exists xxx_book 其意思是：如果数据库中存在xxx_book表，就把它从数据库中drop掉。备份sql中一般都有这样的语句，如果是数据库中有这个表，先drop掉，然后create表，然后再进行数据插入。数据库(Database)是按照数据结构来...
As a result,if the column exists, the query returns the column name. Otherwise,we get no results. 6. Conclusion In this article, we saw how to check whether a column exists within a table. Overall, we worked with three different DBMSs: ...
SELECT column_name(s) FROM table_name WHERE EXISTS (subquery); 在这个语法中,column_name(s)是要检索的列名,table_name是要从中检索数据的表名,subquery是一个子查询,用于检查是否存在满足特定条件的行。 SQL EXIST语句的优势是可以在查询中使用子查询来进行复杂的条件判断。它可以用于过滤查询结果,只返回满足...
`s_table_name` nvarchar(255) ) RETURNS tinyint(1) DETERMINISTIC BEGIN IF EXISTS ( SELECT 1 FROM Information_schema.tables WHERE table_name = s_table_name AND table_schema = s_database_name ) THEN return true; else return false; end if; END| DELIMITER ; -...