how can period_days checking

Question

scheme :combobx

two datepicker and show btn.

from and to datepicker.

show btn click customer name,loan amount, fromdate and todate display.

two table using .

Ist table in scheme name and period_days(eg:scheme a=365,B=4)

two date checking (period_days) checking
The result in period_days closing date display.

how can query creating

select  vLoan_No As LoanNumaber,dIssue_Date As Date,vParty_Id As CustomerName,dcLoan_Amt As LoanAmount,dDue_Date As DueDate from tbl_LoanMaster  where scheme_name and period_days>=from and todate ***how creating