Обсуждение: sort order with < & > in varchar fields

Поиск
Список
Период
Сортировка

sort order with < & > in varchar fields

От
Rolf Johansson
Дата:
It is possible to extract rows in a table using
SELECT name FROM table WHERE name >= 'Bergman'.

The problem I have is that I get names like "Berg, Paul"
with this query, and I don't want that.

Is there documentation on how >= and <= works with varchar
fields? Does pg count in the "," character or ignore it?
And so on...

Version is 7.0.1.

/Rolf


Re: sort order with < & > in varchar fields

От
Tom Lane
Дата:
Rolf Johansson <rojo@nocrew.org> writes:
> Is there documentation on how >= and <= works with varchar
> fields? Does pg count in the "," character or ignore it?

That depends.  If you compiled with --enable-locale then it's
whatever strcoll() says for the locale you are running the
postmaster in.  If not, it's whatever strcmp() says, which is
normally plain ASCII collation order.

Note: beware of changing the postmaster's locale on the fly;
this can leave your indexes on textual columns out of order and
hence effectively corrupt.  You can fix that by dropping/rebuilding
such indexes, or with REINDEX.
        regards, tom lane