TSQL XCHECK COLLUMN VALUE code example
Example 1: sql constraint check value in list
ALTER TABLE <table>
ADD CONSTRAINT chk_val CHECK (col in ('yes','no','maybe'))
Example 2: how to check default value of column in sql server
SELECT object_definition(default_object_id) AS definition
FROM sys.columns
WHERE name ='colname'
AND object_id = object_id('dbo.tablename')