What is the default column name given to a TABLE() type with a single column

Question

CREATE OR REPLACE TYPE MISSING_KEYS AS TABLE OF VARCHAR2(256);
SELECT [¿what goes here?] as missing_key
FROM TABLE (MISSING_KEYS('A','B','C','D'))

What is the default column name that should be in [¿what goes here?] in the above example?

Answer 1

column_value Pseudocolumn

When you refer to an XMLTable construct without the COLUMNS clause, or when you use the TABLE function to refer to a scalar nested table type, the database returns a virtual table with a single column. This name of this pseudocolumn is COLUMN_VALUE.

Example:

CREATE OR REPLACE TYPE MISSING_KEYS AS TABLE OF VARCHAR2(256);
SELECT column_value AS missing_key
FROM TABLE (MISSING_KEYS('A','B','C','D'))