Re: enums

Jim C. Nasby wrote:

>
>On another note, I noticed that the comparison operators seem to be
>comparing the underlying numeric value used to store the enum, which is
>wrong IMO. Consider:
>
>ENUM color '"red","blue","green"'
>CREATE TABLE t (c color);
>INSERT INTO t VALUES('blue');
>INSERT INTO t VALUES('green');
>INSERT INTO t VALUES('red');
>SELECT c FROM t ORDER BY c;
>red
>blue
>green
>
>That seems counter-intuitive. It's also exposing an implimentation
>detail (that the enum is stored internally as a number).
>
>

No it is not. Not in the slightest. It is honoring the enumeration order
defined for the type. That is the ONLY correct behaviour, IMNSHO.
Otherwise, you could just as easily use a domain with a check constraint.

In fact, mysql's behaviour is laughably, even ludicrously, inconsistent:

mysql> select color from t order by color;
+-------+
| color |
+-------+
| red |
| blue |
| green |
+-------+
3 rows in set (0.06 sec)

mysql> select * from t where color < 'green';
+-------+
| color |
+-------+
| blue |
+-------+

So for "order by" it honors the enumeration order, but for < it uses the
lexical ordering. Lovely, eh?

cheers

andrew