Subject Re: [Firebird-Architect] Substring
Author Ann W. Harrison
Hi Arno,

>The end-position (E) is S+L, thus your examples
> > substring ('abcdefghij' from 1 for 5) => 'abcde'
> > substring ('abcdefghij' from 0 for 5) => 'abcd'
> > substring ('abcdefghij' from -1 for 5) => 'abc'
>are right.

That agrees with what I understood from the SQL-92 document.
It's an error to supply a negative length or a start that
comes after the end of the string, but otherwise, anything
goes. What a useful construct.