Update Statement using IF or Else

[IAMINFO]

Hello everyone I am not sure how to write this sql statement correctly,please help.

I have 4 columns below
The 2 left columns are flags that can be set as Y or N depending on the values in the right columns

If any column on the right is not null
the flags on the left should read AnyDet = 'Y' and NoDet = 'N'

If both columns on the right are null
the flags should read AnyDet = 'N' and NoDet ='Y'

col-1 col-2 col-3 col-4
AnyDet - NoDet DocDet DetDet

I am not sure how to right this please help, I have been stuck on this for 2 days, not sure how to proceed
Thank you for reading this post.

 

[drlex]

You don't mention what should happen when neither of the right two columns are NULL.

Assuming that there should be no change in those columns in that situation, how about

update [TABLENAME]
set [AnyDet] = case when [DocDet] is NULL and [DetDet] is NULL then 'N' when [DocDet] is NULL or [DetDet] is NULL then 'Y' else [AnyDet] end,
[NoDet] = case when [DocDet] is NULL and [DetDet] is NULL then 'Y' when [DocDet] is NULL or [DetDet] is NULL then 'N' else [NoDet] end

?

soi la, soi carré