What if you want to include non-matches against T3 ? Would you add to the WHERE clause ?
and T3.COL1 is NULL
and T3.COL2 is NULL
and T3.COL3 is NULL
and T3.COL4 is NULL
I guess it depends on what you are actually trying to do but if any of the t3 columns are NULL, they won't match any of the t2 columns even if they are also NULL so the result is that the rows won't exist and the WHERE NOT EXISTS will still work.
is pronounced ree-bar and is a Modenism for R
First step towards the paradigm shift of writing Set Based code: Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column.
If you think its expensive to hire a professional to do the job, wait until you hire an amateur. -- Red Adair
How to post code problemsHow to post performance problemsForum FAQs