Question

I read ORDER BY condition and How to add condition in 'order by'? but these don’t answer to my issue.

I have 2 datetime columns called CREATION_DATE and UPDATE_DATE.

I want to sort (using ORDER BY clause) by :

• CREATION_DATE if CREATION_DATE = UPDATE_DATE

  or

• UPDATE_DATE in other case.

I wrote

SELECT * FROM Table1
ORDER BY
CASE Table1.CREATION_DATE
    WHEN Table1.CREATION_DATE = Table1.UPDATE_DATE THEN Table1.CREATION_DATE
    ELSE Table1.UPDATE_DATE
END ASC

but it does not work, I get an error at the = symbol.

I tried with other operators… Of course, I make mistake but I don’t know if is correct to use operators in WHEN statement.

Is not accepted operators in WHEN ?

Thank you

Answer 1

try

ORDER BY
CASE WHEN Table1.CREATION_DATE = Table1.UPDATE_DATE
     THEN Table1.CREATION_DATE
     ELSE Table1.UPDATE_DATE
END ASC

or simpler

ORDER BY Table1.UPDATE_DATE ASC

since you want to order by UPDATE_DATE only if it is equal to CREATION_DATE. In that case you could order by UPDATE_DATE too. In other cases you want to oder by UPDATE_DATE. So just only order by that. It is the same.