On 5/1/19 11:04 AM, Francisco Olarte wrote:
Adrian:
On Wed, May 1, 2019 at 7:57 PM Adrian Klaver <adrian.kla...@aklaver.com> wrote:
You will have to explain further as I am not seeing it:
test_(postgres)# select '2019-05-01 9:52' <= '2019-05-01 24:00'::timestamp;
?column?
----------
t
test_(postgres)# select '2019-05-01 24:00' <= '2019-05-01 24:00'::timestamp;
?column?
----------
t
Because you are using two selected examples. The one with 9:52 is ok.
The last one is misleading because you are using a constant for a
particular timestamp in MAY THE SECOND wich can be written to look
like it is in MAY THE FIRST.
Rewrite it as
select '2019-05-02'::timestamp <= '2019-05-01 24:00'::timestamp;
And you'll see and out of range date selected.
Technically it is correct as:
test_(postgres)# select '2019-05-02'::timestamp;
timestamp
---------------------
2019-05-02 00:00:00
which is Midnight and is both the end of one day and start of another.
It comes down to where you want to draw the line between days.
This is why <= AND 24:00 are bad and misleading.
You may not have problems with 00:00:00 times, but work a bit billing
phone calls and you'll find about one in 86400 hit it ( more in my
case as traffic distribution is skewed ). Use that kind of condition
and you end up chasing why the monthly report has a dozen less calls
than the sum of the daily ones the billing guys made using excel.
Francisco Olarte.
--
Adrian Klaver
adrian.kla...@aklaver.com
