Difference in DATEs

Assume that x and y are of type DATE:

1. AGE( x, y ) < INTERVAL '...' works.

2. x < y + INTERVAL '...' works.

3. x - y < INTERVAL '...' doesn't work (but then, the minus operator is not
defined in the manual for two DATE values).

Question: Is the meaning of x - y well-defined? That is, is there a
definition that I can count on?

Not an important question, but I'm curious, since I like to write date
differences in a style that makes readability/maintenance easy.

-- Dean


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Re: Difference in DATEs

"Dean Gibson (DB Administrator)" writes:
> 3. x - y < INTERVAL '...' doesn't work (but then, the minus operator is not
> defined in the manual for two DATE values).

Sure it is: see 10th row in
http://www.postgresql.org/docs/7.4/static/functions-datetime .html#OPERATORS-DATETIME-TABLE

Forget the interval and compare to an integer.

regards, tom lane

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Re: Difference in DATEs

Tom Lane wrote on 2004-09-21 07:01:
>Sure it is: see 10th row in
>http://www.postgresql.org/docs/7.4/static/functions-datetim e.html#OPERATORS-DATETIME-TABLE
>
>Forget the interval and compare to an integer.

Thanks; that line is not present in the table in the 7.3.4 docs.

-- Dean


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