On Mon, 21 May 2001, Gabor Csuri wrote:
> Hi All again,
>
> after I deleted the "null row" from carname:
> SELECT DISTINCT h_name
> FROM haszon
> WHERE h_name NOT IN (SELECT cn_name FROM carname)
>
> +---+
> | h_name|
> +---+
> | DAEWOO-FSO|
> | DAEWOO-LUBL
Gabor -
Tri-valued logic strikes again. Remember, NULL represents "don't know",
which means "could be anything". So, when you ask the system to return
values that are guaranteed not to be in a list, and that list contains
a NULL, the system returns nothing, since the NULL _could_ be equal to
the
Hi All again,
after I deleted the "null row" from carname:
SELECT DISTINCT h_name
FROM haszon
WHERE h_name NOT IN (SELECT cn_name FROM carname)
+---+
| h_name|
+---+
| DAEWOO-FSO|
| DAEWOO-LUBLIN |
| GAZ |
| TATA |
+---+
Query O
