This might be a bit off topic, but...
[snip]
>
> ... WHERE (product_code = ? OR (? IS NULL AND
> product_code IS NULL))
>
> and bind the same value to both placeholders.
>
> I understand the reasoning for this, and why it's the only way for
> database servers that don't understand "= null".
>
> However this syntax does NOT work with DBD::Sybase because of the way
> OpenClient handles the prepare. The issue is the "? is null" part:
> neither the Sybase client libs, nor the server can determine what
> datatype the placeholder is supposed to be, and I see no way to add a
> directive to tell the server that this item is of the same type as
> "product_code".
Does any database understand ? is null or ? = 3 or ? = 'foo', given that ?
must be a column/function or some other name important for the query parsing
(i.e. not a "value" per se)?
>
> Sybase, on the other hand, understands "= null".
>
That's handy.
> I'll document this in the DBD::Sybase docs, but I just wanted to flag
> the fact that the method documented in the DBI docs is unfortunately
> not portable to Sybase (and *probably* not to ODBC when using a
> Sybase). I don't know if ODBC w/MS-SQL handles this correctly or not.
Which part, the = null or the ? is null?
With SQL Server 2000 and DBD::ODBC,
col_a = null returns no rows
col_a is null returns 1 row
? is null (passing col_a) returns 0 rows
(I suspect dbish is hiding some errors, too)
Jeff
>
> Michael
> --
> Michael Peppler - Data Migrations Inc. - http://www.mbay.net/~mpeppler
> [EMAIL PROTECTED] - [EMAIL PROTECTED]
> International Sybase User Group - http://www.isug.com
>
