DEFAULT [ ( column_name ) ]
Syntax Elements
- column_name
- The name of a column in a base table, view, queue table, or derived table.
- The column name can be qualified or unqualified.
- The DEFAULT function returns the default value of the specified column or derived column (if column_name is omitted).
- If the specified or derived column is a view column or derived table column, the DEFAULT function returns the default value of the underlying table column.
- If the default value of a column evaluates to a system variable, for example when the default value is CURRENT_TIME or USER, the DEFAULT function returns the value of the system variable at the time the statement runs.
- DEFAULT returns null when any of the following conditions are true:
- The specified or derived column was defined with a DEFAULT NULL phrase
- The specified or derived column has no explicit default value
- The specified or derived column is the name of a view column that is derived from a single underlying table column that has no explicit default value
For an example, see “Example: Specifying a View Column Name”.
- The specified or derived column is the name of a view column that is not derived from a single underlying table column, for example, the view column is derived from a literal expression