Perhaps I'm missing something but for each job, wouldn't you just compare the start date of the job with the end date of the other jobs and the end date of the job with the start date of the other jobs? If the end date of the other jobs is less than "the" job, it can't overlap and if the start date of the other jobs is greater than "the" job, it can't over lap there either. I'm thinking that only two conditions are needed instead of 3.