[Zope-DB] Question on ZSQL and Dates

[Dieter Maurer]

Charlie Clark writes:
 > I've been struggling for a while with this one: I need to be able compare
 > dates/ages in a ZSQL-query and don't seem to be able to do it right.
 > 
 > table person
 > name varchar(20),
 > id int,
 > birthdate date
 > 
 > Now I want to be able to select all rows in the table for people who are
 > currently over 45 years old.
 > 
 > SELECT * FROM person
 > WHERE
 > 45 <= '<dtml-var expr="_.DateTime().Date()">' - person.birthdate
Check, how your database performs arithmetic on dates (that's what
happens above). It is quite unlikely that the result is expressed in
years (as you suppose above).


Dieter