[thelist] simple question about comparing dates in PHP/MySQL

[Nan Harbison]

Thanks Rudy! I had come to this conclusion over time (by trial and error)
because it didn't seem to work, but I had no proof. I find the whole date
and time thing in databases a little confusing sometimes.
I am sure I will quote you on this!
Nan 

-----Original Message-----
From: thelist-bounces at lists.evolt.org
[mailto:thelist-bounces at lists.evolt.org] On Behalf Of r937
Sent: Tuesday, July 07, 2009 10:48 PM
To: thelist at lists.evolt.org
Subject: [thelist] simple question about comparing dates in PHP/MySQL

> This might be a stupid question, but someone was trying to tell me 
> that you can compare dates in the format: 2009-06-04 > 2009-05-30.

that is false

as written, those are arithmetic expressions, not dates

2009-06-04 evaluates to the integer 1999, while 2009-05-30 evaluates to the
integer 1974

clearly, not what was intended

written as date strings, however, yes, you can compare them meaningfully

  '2009-06-04' > '2009-05-30'

see the difference?

by the way, lee, mysql does not require date strings to zero-pad the month
or day

furthermore, mysql will recognize any character as the year/month/day
separator, so all of the following are valid dates --

 '2009-05-30'
 '2009-5-30'
 '2009/05/30'
 '2009.5.30'
 '2009?05?30'


rudy
http://simply-sql.com/



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