BEGIN drop_column_if_exists('your_table_name', 'your_column_name'); END; / Method 2: Using Conditional SQL Statements Another way to drop a column if it exists is to use conditional SQL statements. Here's an example: DECLARE v_count NUMBER; BEGIN -- Check if the column exists in th...
代码示例1 DECLARE l_cnt NUMBER; BEGIN SELECT COUNT(*) INTO l_cnt FROM dba_tab_columns WHERE owner = 'my_owner' AND table_name = 'my_table' AND column_name = 'my_column'; IF( l_cnt = 1 ) THEN EXECUTE IMMEDIATE 'ALTER TABLE my_table DROP COLUMN my_column'; END IF; END;...
阿里云计算平台DataWorks(https://help.aliyun.com/document_detail/137663.html) 团队出品,为监控而生的数据库连接池 - 优化 drop column if exists的解析支持 #5797 · ZhengguanLi/druid@8533851
-- column_exists: DROP FUNCTION IF EXISTS column_exists; DELIMITER $$ CREATE FUNCTION column_exists( tname VARCHAR(64), cname VARCHAR(64) ) RETURNS BOOLEAN READS SQL DATA BEGIN RETURN 0 < (SELECT COUNT(*) FROM `INFORMATION_SCHEMA`.`COLUMNS` WHERE `TABLE_SCHEMA` = SCHEMA() AND `TABLE_N...
MOVE TO {partition_scheme_name(column_name) |filegroup_name|“default” } 适用于:SQL Server 2008 (10.0.x) 及更高版本。 SQL 数据库支持"default"作为文件组名称。 指定一个位置,以移动当前处于聚集索引叶级别的数据行。 数据将以堆的形式移动到这一新位置。 可以将分区方案或文件组指定为新位置,但该分...
Transact-SQL 語法慣例 Syntax SQL Server 的語法(檔案群組和 filestream 以外的所有選項都適用於 Azure SQL 資料庫)。 syntaxsql DROPINDEX[IFEXISTS] {<drop_relational_or_xml_or_spatial_index>[ , ...n ] |<drop_backward_compatible_index>[ , ...n ] }<drop_relational_or_xml_or_spatial_index>...
MOVE TO {partition_scheme_name(column_name) |filegroup_name|“default” } 适用于:SQL Server 2008 (10.0.x) 及更高版本。 SQL 数据库支持"default"作为文件组名称。 指定一个位置,以移动当前处于聚集索引叶级别的数据行。 数据将以堆的形式移动到这一新位置。 可以将分区方案或文件组指定为新位置,但该分...
But if the column is already dropped from the database it will through a error as the column is no longer exist. We want to do is to drop a table or column, butonly if it exists Unfortunately there is an IF EXISTS clause for CREATE TABLE in MySQL but no one for ALTER TABLE ADD/...
Option 4 - DROP TABLE IF EXISTS (SQL Server 2016 and up) The previous T-SQL examples will work in all supported versions. However, SQL Server 2016 introduced a simpler way of dropping a table with DROP IF EXISTS. Instead of having to look and see if whether or not the table exists wi...
-- drop column Extension if it exists - all sql server versions IF EXISTS(SELECT 1 FROM sys.columns WHERE name='Extension' AND OBJECT_ID = OBJECT_ID('[dbo].[Employees]')) ALTER TABLE [dbo].[Employees] DROP COLUMN [Extension]; GO SELECT * FROM [dbo].[Employees]; GO ...