The value argument which is indicated in the syntax is an optional parameter that helps to assign an initial value to a variable during the declaration. On the other hand, we can assign or replace the value of the variable on the next steps of the batch. If we don’t make any initial value assigned to a variable, it is initialized as NULL.

The values keyword is probably as old as SQL itself and is pretty well-known for its use with the insert statement. This is, however, just the functionality required by entry-level SQL-92. With full SQL-92, 0 values has a richer semantic: it becomes valid wherever select is valid and can produce multiple rows.

SQLType can be an SQL, user-defined data type. The value () method uses the Transact-SQL CONVERT operator implicitly and tries to convert the result of the XQuery expression, the serialized string representation, from XSD type to the corresponding SQL type specified by Transact-SQL conversion.