Stata: counting for this period and next period

Question

I have a data set similar to this and want to create a count variable under these conditions. If mig is 1 then count how many of un1 or un2 or un3 are 1 and also count how many of un1 or un2 or un3 in the next time period are 1. So I want it to be the count of un* in this period and the next for each individual.

I use the code

egen ... anycount(un1-un3) if mig ==1 & (un1|un2|un3||f.un1|f.un2 |f.un3) 

but I cannot get a count of future values.

Id  t  mig un1 un2 un3 count
1   1   0   0   1   1   
1   2   0   0   0   1   
1   3   1   0   0   1   4
1   4   0   1   1   1   
1   5   0   0   0   0   
2   1   0   0   1   0   
2   2   1   0   0   0   
2   3   0   1   0   0   1
2   4   0   0   0   1   
2   5   0   0   0   0   

Answer 1

To explain this more fully: You have panel data and have tsset Id t or similarly using xtset.

How about

 gen count = cond(mig == 1, un1 + un2 + un3 + F.un1 + F.un2 + F.un3, 0) 

???