I need your help to fix a graph command

[Md Abdul Kader]

I am not sure what is the problem with If logic in this command"graph hbar (mean) typeofviolation if yearin > 1999 && yearin <2010, over(memberstate, sort(position)) title(Type of violationover memberstate(2000-2009)) scheme(plotplainblind)"

Basically, I want to give if logic "more than 1999 and less than 2010"

Thank advance for your help

[Nick Cox]

What error message did you get?

&& should be &

[Md Abdul Kader]

What error message did you get?

&& should be &

Messge is "1999& invalid name"

And it's solved when I use single &
Thank you Nick Cox