Teradata MAX function

问题

Which row will be return if we use following function?

 MAX (NAME)

Where we have following two rows in name column

1 ABC
2 ABC

回答1:

Neither. An aggregate will be returned that is not tied to either row, but rather the Max(Name) value, which will obviously have to be ABC as it's the only value available:

CREATE VOLATILE TABLE test
(
    f1 INTEGER,
    f2 CHAR(3)
) PRIMARY INDEX (f1) ON COMMIT PRESERVE ROWS;
INSERT INTO test VALUES (1, 'ABC');
INSERT INTO test VALUES (2, 'ABC');

SELECT MAX(f2) FROM test;

DROP TABLE test;

Which just returns ABC

You can think of it this way. If I write the number 2 on a whiteboard and ask you to say out loud which one is the largest, you will say "2"; it would be silly to ask "Which 'two' did you pick though?".

回答2:

Since both the values are same and there are only two row,You will get the output as "ABC" when you try to find the max

来源：https://stackoverflow.com/questions/52318683/teradata-max-function