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I was told there would be no (date) math

I was told there would be no (date) math

2006-04-13       - By Michael Ebert

Reply:     1     2     3     4     5     6     7     8     9     10     >>  

I expect it has to do with "Abstract DataType (DATE in this case)
semantics". You can subtract a Date from a Date; the result is a number of
days (a difference). You can subtract a number of days from a date; the
result is a date. That's how your second example gets resolved. In your
first example, the implicit order of execution would be ((DATE - DATE) -
DATE)  which is (#DAYS-DATE) which is not a defined operation for this
ADT...

Dr. Michael Ebert
DB2 & Oracle Database Administrator
aMaDEUS Data Processing
Erding / Munich, Germany


<br><font size=2 face="sans-serif">I expect it has to do with &quot;Abstract
DataType (DATE in this case) semantics&quot;. You can subtract a Date from
a Date; the result is a number of days (a difference). You can subtract
a number of days from a date; the result is a date. That's how your second
example gets resolved. In your first example, the implicit order of execution
would be ((DATE - DATE) - DATE) &nbsp;which is (#DAYS-DATE) which is not
a defined operation for this ADT...</font>
<br>
<br><font size=2 face="sans-serif">Dr. Michael Ebert</font>
<br><font size=2 face="sans-serif">DB2 &amp; Oracle Database Administrator<
/font>
<br><font size=2 face="sans-serif">aMaDEUS Data Processing</font>
<br><font size=2 face="sans-serif">Erding / Munich, Germany</font>
<br>