How to reference once a date

[cmemtsa]

Dear all,

I have various proc sql programs that each contains a clause ' When date = '30Mar2017'D'.

How can I optimize the process by stating at the beginning the date and not changing the date within each proc sql?

Thank you. 

[Kurt_Bremser · Accepted solution]

Use a macro variable:

%let refdate=%sysfunc(inputn(30mar2017,date9.));

and later

when date = &refdate.

[cmemtsa]

Thank you!!!