ALTER TABLE table_name
ALTER COLUMN column_name new_data_type(size);
ALTER TABLE employees
ALTER COLUMN last_name VARCHAR(75) NOT NULL;
ALTER TABLE table_name
ALTER COLUMN column_name column_type;
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Alter Table Customers Alter Column Cust_City nvarchar(100)
Alter Table Customers Alter Column Cust_State nvarchar(100)
sp_rename 'employees.last_name', 'lname', 'COLUMN';
Alter Table [Table Name] Alter Column [Column Name] [datatype]
sp_rename 'table_name.old_column_name', 'new_column_name', 'COLUMN';
ALTER TABLE table_name
DROP COLUMN column_name;