st: How to sum two whole rows by date and time

[Beatrice Crozza <beatrice.crozza@gmail.com>]

Dear All,

maybe it is an easy problem to solve, but I cannot find a way to sort it out!

I would like to sum the entries of two rows:

date              time       x        y    d1    d2 d3  dup
23/01/2008     9:05     99.8           1      .   .      1
23/01/2008     9:05         .       5    .      1   1     2

i would like to sum by date and time, in order to have:

date              time       x        y    d1    d2 d3  dup
23/01/2008     9:05       99.8      5    1     1   1     3


It is not always the case that, for example, one row has the price, in
other words there is not regularity, otherwise I could have used a
time operator to replace the row with the previous one.

I also tried with collapse (sum) but i receive the error message that
a variable cannot be both target and by() and I haven't found a
command similar to egen rowtotal for summing columns.

Thank you very much for any help.

Bea
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/