At 23/01/2002 09:16 AM, you wrote:

> Daniel,
>
> > > The problem is Ab.Name in some cases is null .... and for my
> > >surprise all the operation of concatenating is null. Why? In other
> > databases
> > >the result is Ab.Surname || ', '. This is a bug?
> >
> > This is not a bug. As per SQL-92 standards, this is how a concatenation
> > of
> > strings works.
> >
> Where I can read this?

Here's the text:

2) If <concatenation> is specified, then let S1 and S2 be the result of the
<character value expression> and <character factor>, respectively.
Case:
a) If either S1 or S2 is the null value, then the result of the
<concatenation> is the null value.
b) Otherwise, let S be the string consisting of S1 followed by
S2 and let M be the length of S.

The link is http://docs.linux.cz/sql1992.txt. Look on page 162 of the
document.


Daniel Rail
Senior System Engineer
ACCRA Group Inc. (www.accra.ca)
ACCRA Med Software Inc. (www.accramed.ca)