I have data set from two different time periods, the first periods from the year 1990 to 2019 and the second period is from the year 2006 to 2018. I am a new user to STATA and I want to create a new variable that starts from a specific year to another specific year, for example, the new variable will start from 2006 to 2018. I would be really grateful if someone could help with the code.

Thanks in advance
Ward