views:

50

answers:

2

If i want to use a variable as name of the new column, is this posible in MS SQL?

Example that dont work:

ALTER TABLE my_table ADD @column INT

This worked great for me:

EXEC ('ALTER TABLE my_table ADD ' + @column + ' INT')
+3  A: 

This is possible using dynamic sql to build your DDL and using the EXEC command to execute the string.

Declare @SQL VarChar(1000)

SELECT @SQL = 'ALTER TABLE my_table ADD ' + @column + ' INT'

Exec (@SQL)

See this article.

I will also add that the moment you venture to the land of dynamic sql, you need to take care to not expose yourself to SQL Injection attacks. Always clean up the parameters coming in.

As Philip mentions - think long and hard before doing this. The fact that it is possible does not make it a good thing...

Oded
Also make sure the value of the variable is sanitised for errors and sql injection.
The King
...but its not a particularly good idea, as you could end up with columns named with reserved words (column "column"), or (shudder) containing embedded spaces. Think long and hard before you do this!
Philip Kelley
A: 

Have a look at (EXECUTE (Transact-SQL))

CREATE TABLE MyTable(
        ID INT
)
GO
SELECT * FROM MyTable
GO
DECLARE @column VARCHAR(100)
SET @column = 'MyNewCol'
EXEC('ALTER TABLE MyTable ADD ' + @column + ' INT')
GO
SELECT * FROM MyTable
GO
DROP TABLE MyTable
astander