> ... it seems the "lpad", "rpad" don't work,
> when I type:
> select lpad('laser', 4, 'a');
> in psql, the result is still
> 'laser', the same with 'rpad',
> Is it a bug or I'm mis-understaning the lpad and/or rpad functions?
A simple misunderstanding. The length argument is for the *total*
length. So padding a 5 character string to a length of 4 will do
nothing. But padding to a length of 6 will add a single "a" to the
string.
- Thomas