Thread: 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

"Dean Gibson (DB Administrator)" <postgresql3@ultimeth.com> 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

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-datetime.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