Compare Dates

[Manny Corrao]

I need to compare two dates (i.e. date1 >= date2 or Date1 <= Date2) and thought I would see if someone has some code they might share.

Thanks.

Manny

[Erich Schulman]

GOTO http://www.powerbasic.com/support/pb...ad.php?t=37680

[Aslan Babakhanov]

Not so elegant, but simple and dirty way is to convert date to YYYY-MM-DD format and convert it to long value and then compare them:

MACRO YYYYMMDD_to_Numeric (dt) = VAL(LEFT$(dt,4) & MID$(dt,6,2) & RIGHT$(dt,2))

MACRO YYYYMMDD_Diff (dt1, dt2) = YYYYMMDD_to_Numeric(dt2) - YYYYMMDD_to_Numeric(dt1)        

FUNCTION PBMAIN () AS LONG
     
     LOCAL r1,r2 AS STRING
     r1 = "2009-08-16"
     r2 = "2009-12-31"    
     ? STR$(YYYYMMDD_Diff (r1,r2))

END FUNCTION

[Roger Garstang]

Try converting to Windows FILETIME then use a UNION or other method to get the 64bit values, then you can compare and do math on the value any way you please.

[Egbert Zijlema]

Install Gregorian Library

Why not use my Gregorian Library?
You can simply compare two dates, ranging from 15 October 1582 (the first day of the Gregorian Calendar) to 31 December 9999, inclusive, by comparing their Gregorian Day Numbers, which are LONG INTEGERs.

Frankly, I never thought of this possibility, so a comparision is not in the samples (as far as I remember; maybe I'll ad a wrapper later today). For the time being you must do the comparision-part yourself. You find the library on my website (for url: see my sig below).

[Manny Corrao]

Compare Dates

Thanks all; I appreciate the help.

Manny

[Manny Corrao]

Compare Dates

Using Aslan's suggestion I created the following code to compare two dates. I am sure one of you guru's can clean it up, trim it down and make it Supercalifragilisticexpialidocious.

Thanks again.

DECLARE SUB month(dte$,mnth$)
                    
FUNCTION PBMAIN () AS LONG

     DIM dt AS STRING ' original date
     DIM dt2 AS STRING ' original date

     DIM dt1 AS LONG ' re-arranged date
     DIM dt3 AS LONG ' re-arranged date

     DIM dte$, mnth$

     ' Date 1
     'dt = "2008-12-29"
     dt = "19-JAN-2007"
     dte$ = dt
     mnth$ = ""
     CALL month (dte$,mnth$)
     dt = RIGHT$(dt,4) & mnth$ & LEFT$(dt,2)

     dt = LEFT$(dt,4) & MID$(dt,5,2) & RIGHT$(dt,2)
     dt1 = VAL(dt)

     ' Date 2
     'dt2 = "2009-12-31"
     dt2 = "28-MAY-2008"
     dte$ = dt2
     mnth$ = ""
     CALL month (dte$,mnth$)
     dt2 = RIGHT$(dt2,4) & mnth$ & LEFT$(dt2,2)

     dt2 = LEFT$(dt2,4) & MID$(dt2,5,2) & RIGHT$(dt2,2)
     dt3 = VAL(dt2)

     PRINT dt1, dt1 - dt3
     PRINT dt3, dt3 - dt1

     dte$ = ""
     mnth$ = ""

     WAITKEY$

END FUNCTION

SUB month(dte$, mnth$)

     dte$ = MID$(dte$, 4,3)

     SELECT CASE dte$
            CASE "JAN"
                 mnth$ = "01"
            CASE "FEB"
                 mnth$ = "02"
            CASE "MAR"
                 mnth$ = "03"
            CASE "APR"
                 mnth$ = "04"
            CASE "MAY"
                 mnth$ = "05"
            CASE "JUN"
                 mnth$ = "06"
            CASE "JUL"
                 mnth$ = "07"
            CASE "AUG"
                 mnth$ = "08"
            CASE "SEP"
                 mnth$ = "09"
            CASE "OCT"
                 mnth$ = "10"
            CASE "NOV"
                 mnth$ = "11"
            CASE "DEC"
                 mnth$ = "12"
            CASE ELSE
                 mnth$ = "No Match"
     END SELECT

END SUB

Manny