Need help with formula date range

HI All,

I keep getting errors with below formula: All I want to say is give me the date range inputed including date range for form/to that are null.
Any help is appreciated!

I have to change the date into string because the date is in sting.


(
isnull date({XXXBO_Hosp_Charges_.Admitt_Date}[5 to 6]+"/"+{XXXBO_Hosp_Charges_.Admitt_Date}[7 to 8]+"/"+{XXXBO_Hosp_Charges_.Admitt_Date} )in {?From} to {?To})
or
date({XXXBO_Hosp_Charges_.Admitt_Date}[5 to 6]+"/"+{XXXBO_Hosp_Charges_.Admitt_Date}[7 to 8]+"/"+{XXXBO_Hosp_Charges_.Admitt_Date}[1 to 4]) in {?From} to {?To}