Tom Lane wrote: >> I tested not only with string literals, but also comparing >> table columns of the respective types. > >> I came up with the following table of semantics used for >> comparisons: > >> | CHAR(n)=CHAR(n) | VARCHAR(n)=VARCHAR(n) | CHAR(n)=VARCHAR(n) | >> -----------+-----------------+-----------------------+--------------------+ >> Oracle | PAD SPACE | NO PAD | NO PAD | >> -----------+-----------------+-----------------------+--------------------+ >> PostgreSQL | PAD SPACE | NO PAD | PAD SPACE | >> -----------+-----------------+-----------------------+--------------------+ >> MySQL | PAD SPACE | PAD SPACE | PAD SPACE | >> -----------+-----------------+-----------------------+--------------------+ >> SQL Server | PAD SPACE | PAD SPACE | PAD SPACE | >> -----------+-----------------+-----------------------+--------------------+ > > Interesting. Did you determine which type is assigned to an > unmarked literal string by each system? In Oracle it is treated like a CHAR(n): http://docs.oracle.com/cd/E11882_01/server.112/e26088/sql_elements002.htm#SQLRF51039 "Oracle uses blank-padded comparison semantics only when both values in the comparison are either expressions of data type CHAR, NCHAR, text literals, or values returned by the USER function." I don't know about MySQL and SQL Server, but since they pad strings with space for comparison in all cases, it probably does not make a difference. Yours, Laurenz Albe -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
