Some SQL Server database tables are designed with a default value or an identity specification for every column. If a row in such a table must only use the default values, a special syntax is required to allow an INSERT to be executed.
Using Default Values
Sometimes you will use SQL Server database tables that contain columns that all have default values or are identity columns. If you wish to insert a row using only default values, you cannot provide a column list, as each column in the list must be supplied with an explicit value. In these circumstances you can use the DEFAULT VALUES clause to allow the DBMS to provide the values:
If the table contains columns that do not have defaults, NULLs will be inserted. If there is a column with no default that has a NOT NULL constraint, the insertion will fail.