Friday, September 7, 2012

Check constraint to allow alphabets and numbers only in SQL Server

How to create a check constraint to allow alphabets i.e. A-Z characters only or alphabets + numbers with no special characters in Sql Server?
Here is the scenario, you have column with varchar/char datatype and you don’t want user to any Special characters like ~, !, #, $, %, ^.
Check constraint for allowing Alphabets only 

ALTER TABLE TableName ADD CONSTRAINT Only_Characters CHECK ColumnName NOT LIKE '%[^A-Z ]%' 

Check constraint for allowing Alphabets  + Numbers  only

ALTER TABLE TableName ADD CONSTRAINT Only_Characters_And_Numebrs CHECKColumnName NOT LIKE '%[^A-Z0-9 ]%' 

Note: Remember to add extra space. 


  1. if i want to see only the data contains special characters(apart from a-zA-Z0-9)

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