Problems with a query in Reports6i

Question

Hello,
hope someone can help me with this issue. I have a query like this in my reports:
select c_id ,dat_tim,glo,utr
from ce_pro
where c_id IN ('X1200', 'X1210')
and glo not like 'null' or utr not like 'null'
group by c_id, dat_tim,glo, utr
having dat_tim between '11-JAN-2001'
and '29-JAN-2001'
order dat_tim desc,c_id asc;
If X1200 and X1210 have glo or utr like null, then this query give me other c_id(for example X909 and X880) values different from X1200 and
X1210 because they have glo not like null or utr not like null.
What I like to get is this:If X1200 and X1210 have glo and utr values like null, then my query shall only return
X1200 and X1210 with glo and utr like null. It seems like
the condition glo not like 'null' or utr not like 'null' decide the outcome of my query and not the condition c_id IN ('X1200', 'X1210'). Hope someone can help.
Best Regards
Roar

Answer 1

Well I can tell you this - Unless you physically store the value 'NULL' in the database, that is the reason you are not pulling back the values you expect.
If a column does not have a value, then its value is null. You can NEVER use =, <>, or like with a null value. The null value does not exist, so saying like 'null' is useless.
And besides, why are you using like in this case? Since you dont have the % % wildcards, like in this case would be equivalent to =. Both of which are not valid with null.
Hopefully this will help you a bit - if not, post the table descriptions and some sample data to show what the query is bringing back. I think you should work on the null/not null part first.