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22 Φεβ 2017 · Using Exists statement to delete data from table: IF EXISTS(SELECT 1 FROM Your_table WHERE user_id = user_id) BEGIN DELETE FROM Your_table WHERE user_id= user_id END Delete table from database : IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'TheSchema' AND TABLE_NAME = 'TheTable') BEGIN --Your delete statement END
30 Αυγ 2012 · If the row exists in both the source and target, UPDATE the target; If the row only exists in the source, INSERT the row into the target; (Optionally) If the row exists in the target but not the source, DELETE the row from the target. Developers-turned-DBAs often naïvely write it row-by-row, like this: -- For each row in source.
22 Αυγ 2016 · Create new database object. The new DROP IF EXISTS syntax replaces the old block of code that used system catalog views to determine the existence of an object. Basically, the new syntax combines steps one and two into a smaller set of code to produce the same results.
6 Οκτ 2008 · How can ALTER be used to drop a column in a MySQL table if that column exists? I know I can use ALTER TABLE my_table DROP COLUMN my_column, but that will throw an error if my_column does not exist. Is there alternative syntax for dropping the column conditionally? I'm using MySQL version 4.0.18. mysql. ddl. mysql4. edited May 15, 2019 at 1:16.
10 Οκτ 2011 · I have the following SQL query in my Ruby app: sql = "DELETE FROM `#{database}`.`table1` WHERE `same_id` = #{some_id};" The problem is that in rare circumstances table1 might not exist. I need to construct this query so even if the table does not exist SQL does not throw an error.
To remove an existing database from a SQL Server instance, you use the DROP DATABASE statement. The DROP DATABASE statement allows you to delete one or more databases with the following syntax: DROP DATABASE [ IF EXISTS ] database_name [,database_name2,...];
16 Ιαν 2015 · In SQL Server you could do something like this. IF EXISTS ( SELECT 1. FROM sys.objects AS o.
