is it possible to do a conditional concat?-CodePudding

I have a query that pulls different data but for one field it concats its since the URL is partially filled in my db

select blah, blah2, blah3, concat('https://my_url.com', g.logourl ) as logourl

but the problem is if logourl is blank then I just get https://my_url.com instead of the full URL. This is having down stream impact.

Is there a way to only concat if logurl is not null?

CodePudding user response：

You can try using case when expression

select blah, blah2, blah3, 
 case when g.logourl is not null or g.logourl<>''
     then concat('https://my_url.com', g.logourl ) end as logourl

CodePudding user response：

You can use:

(case when g.logourl is not null  then 'https://my_url.com' || g.logourl 
 end) as logourl

If you want to avoid an empty string (and NULL) you can use:

(case when g.logourl <> ''  then 'https://my_url.com' || g.logourl 
 end) as logourl

If you want to eliminate a string of spaces:

(case when replace(g.logourl, ' ', '') <> ''  then 'https://my_url.com' || g.logourl 
 end) as logourl

CodePudding user response：

If you want the output to be null if logurl is null, then you can use the concat operator || instead of the concat() function

select 'a' || null;
 ?column?
----------

(1 row)