Question

I have two different columns as DateTime type : CREATION_DATE and UPDATE_DATE

I want to create a SELECT (some fields) statement which order by the column (UPDATE_DATE or CREATION_DATE not both) where UPDATE_DATE > CREATION_DATE and UPDATE_DATE must be NOT NULL

Why ? Any items will be create in DB and CREATION_DATE will be filled automatically but not UPDATE_DATE column.

When somebody modify an existing item then the UPDATE_DATE will be filled/updated at every modification and will be listed on UserInterface by UPDATE_DATE (ascendent).

How to do that ?

Sorry if my question is bad …

Answer 1

Use isnull, if UPDATE_DATE is null it uses CREATION_DATE to order rows.

select * 
from table
order by isnull(UPDATE_DATE, CREATION_DATE) asc

Read more about isnull on MSDN.

coalesce is an alternative and it’s going to work in most RDBMS (afaik).

select * 
from table
order by coalesce(UPDATE_DATE, CREATION_DATE) asc