Question

Using Informix, I’ve created a tempory table which I am trying to populate from a select statement. After this, I want to do an update, to populate more fields in the tempory table.

So I’m doing something like;

create temp table _results (group_ser int, item_ser int, restype char(4));  insert into _results (group_ser, item_ser) select        group_ser, item_ser, null from       sometable 

But you can’t select null.

For example;

select first 1 current from systables 

works but

select first 1 null from systables 

fails!

(Don’t get me started on why I can’t just do a SQL Server like ‘select current’ with no table specified!)

Answer 1

This page says the reason you can’t do that is because ‘NULL’ doesn’t have a type. So, the workaround is to create a sproc that simply returns NULL in the type you want.

That sounds like a pretty bad solution to me though. Maybe you could create a variable in your script, set it to null, then select that variable instead? Something like this:

DEFINE dummy INT; LET dummy = NULL;  SELECT group_ser, item_ser, dummy FROM sometable