>Hello Friends,
>
>I have to apply following validation in my form. I am not sure whether this can
>be accomplished by sql and if yes then how ? Any help is highly appreciated.
>
>I have two fields like following.
>
>dStart dStop
>
>06/14/99 06/20/99
>06/22/99 06/25/99
>
>Now, a new start and stop date can't overlap with others.
>
>06/14/99 - 06/21/99
>06/15/99 - 06/20/99
>for example here are some invalid date ranges for new record.
>
>
>These are not allowed because they are overlapping with previous records.
>
>Thanks in Advance for all your help.
>
>Thanks
>Mark

Do you want to find all records with invalid dates?

for invalid start dates:
SELECT * FROM MyTable Copy1
WHERE dStart IN
(SELECT dStart FROM MyTable Copy2 WHERE BETWEEN(Copy1.dStart, Copy2.dStart, Copy.dEnd)

for invalid end dates:
SELECT * FROM MyTable Copy1
WHERE dEnd IN
(SELECT dEnd FROM MyTable Copy2 WHERE BETWEEN(Copy1.dEnd, Copy2.dStart, Copy.dEnd)

To just validate one set of start and end dates, use Cindy's excellent example.