On Dec 12, 2007 1:51 PM, Dennis Cote <[EMAIL PROTECTED]> wrote:
> C M wrote:
> >
> > Thanks to you both--using the || did the trick, and I can try the other
> > approaches mentioned as well. In Python Igor's suggestion was just:
> >
> > amount = "+1"
> > cur.execute('SELECT string, d FROM test WHERE d >= date("now", ? || ? ||
> "
> > days")',amount)
> >
> >
> You will might be better off building the entire argument string in
> Python and then binding that string to a single argument to the date
> function in the SQL. You can then use the same query to do offsets in
> hours, days, months, or years for example. It will probably be slightly
> faster as well since SQLite will be parsing an executing a simpler SQL
> statement.
>
> You should also invert your string quoting in Python. SQL uses single
> quotes for literal values, and double quotes for identifiers (such as
> table and column names). SQLite accepts double quotes around literals as
> an extension, but it can get you into trouble if you have a column with
> the same name as your literal value. In that case it will be interpreted
> as the column name. You might even want to use Python's triple quotes to
> allow both single and double quotes to be used in the SQL string itself.
>
> Note, the plus character in '+1 days' is not needed. It is simply a sign
> character, it does not signify addition. You only need the sign if you
> want a negative offset.
>
> amount = 1
> unit = "days"
> offset = str(amount) + " " + unit
> cur.execute("SELECT string, d FROM test WHERE d >= date('now', ?)",
> offset)
>
>
> HTH
> Dennis Cote
>
Thank you--very useful to know.
