stratifying a conditional logistic regression model by another variable

[Sakshi Rajatbhai Tewari]

it might be a silly question, but it is my first time doing a conditional logistic regression model in a case control study. For one table, we are stratifying our model by a variable with 2 levels. Lets say this variable is "stratifyingvar" and is basically what the cases and controls reported in their surveys. My question is, can i do this with a simple "if " condition

clogit outcome exposure if stratifyingvar==1 , group(matchid) or

clogit outcome exposure if stratifyingvar==0, group(matchid) or

or do i have to create another variable for this purpose, where in all the controls matched to a case would have the case's value of the stratifying variable (instead of what they reported) , and then do the if statement using this new variable (lets call it stratifyingvar2)

clogit outcome exposure if stratifyingvar2==1 , group(matchid) or

clogit outcome exposure if stratifyingvar2==0, group(matchid) or