On Thu, 7 Nov 2002, Tom Lane wrote: > Stephan Szabo <[EMAIL PROTECTED]> writes: > > On Thu, 7 Nov 2002, Ludwig Lim wrote: > >> SELECT CAST ( (NULL*NULL) AS NUMERIC(2,0)); > >> Cannot cast type '"char"' to '"numeric"' > > > It seems to me that it's trying to decide on a type > > for the expression NULL * NULL. It's a NULL, but a > > NULL of what type? > > Yeah, and it's picking "char" (the single-byte datatype), because > (a) the NULLs are initially regarded as type UNKNOWN, and (b) if we > don't have any other way to make a decision we try assuming that > UNKNOWNs are of string category, and (c) the only datatype in string > category that has a "*" operator is "char". > > I am kind of inclined to remove the arithmetic operators on "char" > (+,-,*,/) in 7.4 --- they don't seem to have any real-world uses, > and as this example illustrates, they are perfectly positioned to > capture cases that probably ought to be errors.
That seems to make sense. I assume that they were there so that someone could treat it as a 1 byte integer? ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
