Hi,

I am totally new to Stata (Version 17.0). I´ve got a data set icluding the variables ticker (some kind of ID Code for each company, ZOTS and ZY in the extract below) and anndats (announcement dates) as well as multiple other variables.
Now I need to drop all observations, where ticker and anndats are the same.

Here is an extract from list ticker anndats:

ZOTS 03nov2015
ZOTS 16feb2016
ZOTS 16feb2016
ZOTS 04may2016
ZOTS 04may2016
---------------------------
ZY 15nov2016
ZY 22feb2017
ZY 22feb2017
ZY 16may2017



Like, for example, i want to drop the third, the fifth and the eigth row, but keep the rest. How do I do that?