Greetings, I've reviewed the Statalist forum in order to seek an answer for my particular case. However, even when there are plenty of similar topics, I couldn't find my specific case to solve the problem.

I got a data set where I extracted the Month and the Year (both numerical) as the next table shows.


Code:
Year    Month_Num
1990    1
1990    2
1990    3
1990    4
1990    5
1990    6

I have tried combining Month_Num and Year into a single variable which is a string variable of the form:


Code:
Year    Month_Num    YM
1990    1                   1-1990
1990    2                   2-1990
1990    3                   3-1990
1990    4                   4-1990
1990    5                   5-1990
1990    6                   6-1990

But when I use
gen date=date(YM, "MY")
format date %tm

It produces results way strange,

Code:
Year    Month_Num    YM    date
1990    1                  1-1990    2873m3
1990    2                  2-1990    2875m10
1990    3                  3-1990    2878m2
1990    4                  4-1990    2880m9
1990    5                  5-1990    2883m3
1990    6                  6-1990    2885m10


I know there should be an easy way by just using the Month_Num and Year variable and put them together and simply format it as time monthly. But I wasn't able to figure out a solution.

Thank you for your time.