Naomi,

1) I doubt the table is so large that it'd make much difference, and if the table so large it should be in a higher performance database engine for lots of reasons.

2) This also seems like it's a once-a-day or once-a-week query to send out a company email wishing people happy birthday

3) I can't imagine too many person tables that'd bother building an index on DOB that's not a field used for filtering many results so the cost of a table scan isn't all that bad (see item 1).

>I don't really like all the suggestions, because they don't use existing index on date, if there is an index. I think we need to convert ldStart and ldEnd to the year of DOB and not vs. versa.