1. In Object Explorer, right-click the table to which they want to delete columns and choose Design (Modify in SP1 or earlier).
Table Designer opens.
2. Select the column they want to delete.
3. Right-click the column and choose Delete Column from the shortcut menu.
4. If the column participates in a relationship, a message prompts them to confirm the deletion of the selected columns and their relationships. Choose Yes.If the column does participate in a check constraint, the database server will reject developers’ modification when they try to save their work. To delete a column that participates in a check constraint, they must first modify or remove the check constraint before they can delete the column.