Question

Say I have the following table:

ID  Value
--  ----
1   1
1   1
1   0
2   1
2   1

let us take the ID of 1. I need to check that all of the ID’s that are 1 have a value of 1.
If not, I need to return ‘N/A’. In this case, since row 3 had a value of 0, I need to return ‘N/A’

    select * from tbl1 where ID = 1 and value = 1

will not quite do it.

I know SQL has the ALL keyword but not sure how to use it in this case

Answer 1

DECLARE @id INT;
SET @id = 1;

SELECT CASE 
  WHEN EXISTS (SELECT 1 FROM dbo.tablename WHERE ID = @id AND Value <> 1) THEN 'N/A'
  WHEN EXISTS (SELECT 1 FROM dbo.tablename WHERE ID = @id) THEN 'All are equal to 1'
  ELSE 'No values present with this ID.'
END