Hi again,
new query for the summation
Drug1 Drug2
-------- -------
1 .
3 .
. 1
2 .
. 5
I want to have new variable "drugs" containing the values of drug1 and
drug2 together, but when i make summation, it is generating missing
values because drug1 and drug2 can not have numerical values at the
same time, of one obs had data, the other will be empty for sure.
Any tips?
Thank you and best regards
ziad
*
* 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/
