with 3 columns (variables) of different dates. How can Stata identify/keep the earliest date for each observation?
AG
**********************************************************************
This message may contain confidential and privileged information.
If you are not the intended recipient please accept our apologies.
Please do not disclose, copy or distribute information in this e-mail
or take any action in reliance on its contents: to do so is strictly
prohibited and may be unlawful. Please inform us that this message has
gone astray before deleting it. Thank you for your co-operation.
NHSmail is used daily by over 100,000 staff in the NHS. Over a million
messages are sent every day by the system. To find out why more and
more NHS personnel are switching to this NHS Connecting for Health
system please visit www.connectingforhealth.nhs.uk/nhsmail
**********************************************************************
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
