Fill blank spaces in SQL table

Hi

I've got 2 columns fields in a table.

Field1 is awlays populated with data
Field 2 is mostly blank.

How do I populate field2 with data from field 1 if field 2 is empty, but only if field2 is empty?

Thanks
EdAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

jwentingCommented:
You want to do that on inserting a record or at a later date?
If the former, use a trigger on post-insert. See documentation for your database engine on how to implement triggers.

If the latter, a simple update query will do:
update mu_table set column2 = column1 where column2 is null;

commit that and you're done.
0
mnialonCommented:
hello
please try the following :

update t1 set field2 = field1 where field2 is null

regards,

0
Kevin CrossChief Technology OfficerCommented:
The above are correct.  However, if your field can be empty string '' instead of null, then just adjust like this:
update your_table_name
set field2 = field1
where isnull(field2, '') = ''

Open in new window

0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Newly released Acronis True Image 2019

In announcing the release of the 15th Anniversary Edition of Acronis True Image 2019, the company revealed that its artificial intelligence-based anti-ransomware technology – stopped more than 200,000 ransomware attacks on 150,000 customers last year.

brejkCommented:
If blank means an empty string:

UPDATE YourTable
SET Field2 = Field1
WHERE Field2 = ''
0
brejkCommented:
@mwvisa1: If field2 is indexed the better would be:

update your_table_name
set field2 = field1
where field2 = '' or field2 is null
0
Kevin CrossChief Technology OfficerCommented:
I typically don't worry about performance on one time data cleanup activities, but you are correct that should always code to take advantage of indexes.  As a programmer, I like checking for NULL first then compare as string, BTW. :) habit!

0
Kevin CrossChief Technology OfficerCommented:
@brejk: And I should correct that, I don't worry on simple stuff like this. :) I would be in trouble if I ran anything too nasty on a production system...
0
brejkCommented:
@mwvisa1: What a sad world would be without our habits ;-)
0
shru_0409Commented:
nvl(field2,field1)
or
nullif(field1,field2)
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft SQL Server 2005

From novice to tech pro — start learning today.