Am 26.04.2010 12:11, schrieb Takahiro Itagaki:
> The problem is not in ascii(), but in casting from char to text.
> We have only one version of ascii() in default; ascii(text).
> So, if you use ascii( ' '::char(1) ), it is actually handled as
> ascii( ' '::char(1)::text ). Traling spaces were removed during
> the cast to text.
Ok, that makes sense.
> Do you know how the SQL standard mention the behavior? IMHO, postgres'
> behavior is more reasonable because length(' '::char(1)) is 0.
Just found http://troels.arvin.dk/db/rdbms/ which claims that this is
against the standard:
"PostgreSQL: Stores CHARs in space padded form, but violates
the standard by (conceptually) truncating trailing white-space
before performing most functions, operators, and comparisons
(like the CHARACTER_LENGTH-function and the concatenation(||)
operator)."
Not sure if this is correct and how well-defined the SQL standard
actually is in this regard. It seems Oracle does not remove trailing
spaces when converting from char to varchar.
-- Christoph
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