Tech Tip: Elapsed Time Function

[Guest.Visitor]

I am little confused. Why would I want to write an entire procedure to do what is already available (and BETTER!) in RPG? You are using Date and Time fields. Why not use a Timestamp field? This would allow to calculate elpased times less than a second (of course how accurate would these times really be??). You are using the %Diff() BIF. Why not use the %Diff() against the 2 Timestamp fields directly? You are using you own code to return the elapsed time in different units (Hours, Days, etc.). Why not use the optional 3rd parm on %Diff()? As you can see, ALL of the functionallity you have written into your procedure are directly available by using 2 Timestamp fields (with the TIME op-code) and the %Diff() BIF. So, what's the point? Brian

[Guest.Visitor]

If you've already got the "From" and "To", why not just use the SUBDUR opcode, then you'll get the difference with one line of code. Matt

[Guest.Visitor]

What you're saying is true; however, that could be said of any user-defined function. The point of this is to take what would otherwise be a multi-step process and convert it into a format that can be used on a single EVAL statement. While this can be accomplished with SUBDUR, the function will do both date and time in one step. The tech tip itself was written in response to a question that I've heard other iSeries programmers ask. Mike

[Guest.Visitor]

Another way to easily compute duration given two dates and times is using builtin function %DIFF() as follows: dur=%diff(d1+t1:d2+t2:*minutes); That is, you can "add" together a date value and a time value to get a timestamp value, and you can then compute the difference of the two timestamps. Cheers! Hans

[Guest.Visitor]

Hello, why using a couple of statements, when SQL needs only one. Here an example how to calulate date/time difference with embedded SQL: Birgitta

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[MCWebsite.Staff]

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