If statement is not working

[KHALID MEDANI]

I am new to stata and only use it for metanalaysis , I have imported the data from excel, the 3d column name is Group which has AC and AT groups , I used the metan code: metan p LCI UCI if Group==AC , label (namevar=Author, yearvar=year)
I got error r(111): AC not found
I ran the metan code without the if statement and it ran smoothly , This is my first time to use if statement in stata , what do I need to do?
thank you

[Nick Cox]

If AC is a string value you need to write

… if Group ==  “AC”

[KHALID MEDANI]

And that is perfectly solved the Problem. Thanks a lot Nick