SQL question about returning a row even if one of the selects are null

[JMaster]

I'm writing a SQL query (Postgresql) where I'm grabbing 6 different things:
i.e. select a, b, c, d, e, etc...
If e is empty, I still want to pull that record with e = null. Am I supposed to use coalesce(e, 'null')?

By the way, e comes from I.g = J.g AND J.f = K.f AND K.e = L.e, where I have I.g to start with.
Sometimes J has a value for the "e column" and sometimes it doesn't. If it has it, I want to get e and if it doesn't, I want to get "null".

 

[HJB417]

In mysql, you can do

"SELECT a, b, c, d, IFNULL(e, 'null')"

try it in postgres and see how it goes, though make sure you're using the right null checking function.

 

[kamper]

So you want to get a string back with the word "null" instead of an sql null value? Both your solution and HJB417s sound reasonable.

I don't know why you'd ever want to do that though. Sql null was created like it is for a reason. A better solution would be to detect the null at the app level and substitute the string yourself. That way you don't get screwed by the odd chance that e is actually the string "null" in the database.

 

[mAdMaLuDaWg]

Update tablename set E='NULL' where E is NULL
and set the default value of E to 'NULL'

 

[Jeraden]

Yes, coalesce is what you want for postgresql.

 

[ttown]

edit: nm.... would help if I could read...