Question

I have a table in which all the records have an id, timestamp, and a Boolean value. I need to discover in which records the Boolean changes to false within 1 second of it being true for the same id.

I’ve been working on the following statement, but after doing some research, I feel either a CASE combined with a FETCH statement might work better, but I haven’t found a good example where they’ve been used together.

SELECT *  
FROM Table_1  
WHERE timestamp IN(  
    SELECT DATEADD(Second, 1, timestamp)  
    from Table_1  
    where Boolean = 1)  
AND ID in (  
    SELECT ID   
    from Table_1 where Boolean = 1)  
AND Boolean = 0

Answer 1

How about:

Select Distinct
  t1.id
From
  Table_1 t1
    Inner Join
  Table_1 t2
    On
      t1.Id = t2.Id And 
      t1.Boolean = True And 
      t2.Boolean = False And
      DateDiff(Second, t1.Timestamp, t2.Timestamp) Between 0 And 1

a matter of taste as to how much of that you put in the join clause and how much you put into a where clause.

Edits

• added distinct
• put minimum bound on date difference