>
>
>-Ursprüngliche Nachricht-
>Von: RSmith [mailto:rsm...@rsweb.co.za]
>Gesendet: Freitag, 20. Dezember 2013 14:20
>An: General Discussion of SQLite Database
>Betreff: Re: [sqlite] Does not detect invalid column name when subexpression
>optimized away
>
&g
On 2013/12/20 14:09, Simon Slavin wrote:
On 20 Dec 2013, at 12:05pm, Dan Kennedy wrote:
"1 OR unknown" is not unknown, it is 1. And so on. To summarize:
sqlite> SELECT (0 AND NULL), (1 AND NULL), (0 OR NULL), (1 OR NULL);
0|null|null|1
Well if you're so smart,
(A) Anything divided by i
On 20 Dec 2013, at 12:05pm, Dan Kennedy wrote:
> "1 OR unknown" is not unknown, it is 1. And so on. To summarize:
>
> sqlite> SELECT (0 AND NULL), (1 AND NULL), (0 OR NULL), (1 OR NULL);
> 0|null|null|1
Well if you're so smart,
(A) Anything divided by itself is 1.
(B) Anything divided by ze
; SELECT (0 OR NULL);
null
"1 OR unknown" is not unknown, it is 1. And so on. To summarize:
sqlite> SELECT (0 AND NULL), (1 AND NULL), (0 OR NULL), (1 OR NULL);
0|null|null|1
Dan.
David
On Thu, 12/19/13, Richard Hipp wrote:
S
On 20 Dec 2013, at 4:11am, David Bicking wrote:
> But isn't NULL and 0 a NULL? So wouldn't it need to evaluate X to determine
> if it was null, and thus discover it wasn't a valid column name and return an
> error?
In SQL, where anything can be NULL, binary operation tables must be written ou
On 2013/12/20 06:11, David Bicking wrote:
But isn't NULL and 0 a NULL? So wouldn't it need to evaluate X to determine if
it was null, and thus discover it wasn't a valid column name and return an
error?
David
It's hard to make a case for it though. I could argue both sides from first
princ
Does not detect invalid column name when subexpression
optimized away
To: "R Smith" , "General Discussion of SQLite Database"
Cc: amb...@math.bme.hu
Date: Thursday, December 19, 2013, 9:27 PM
On Thu, Dec 19, 2013 at
6:36 PM, RSmith
wrote:
> my guess is
the optim
On Thu, Dec 19, 2013 at 6:36 PM, RSmith wrote:
> my guess is the optimiser pounces directly on the fact that (X and 0)
> will always be 0
>
Correct. The code is at
http://www.sqlite.org/src/artifact/962c2988?ln=556-559
sqlite3ExprAnd() gets called to build the AND operator directly from
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On 19/12/13 15:36, RSmith wrote:
> With this query you essentially ask the RDBMS to evaluate and supply
> you with the result of (X and 0) - my guess is the optimiser pounces
> directly on the fact that (X and 0) will always be 0 no matter what X
> is
With this query you essentially ask the RDBMS to evaluate and supply you with the result of (X and 0) - my guess is the optimiser
pounces directly on the fact that (X and 0) will always be 0 no matter what X is so that it does not bother trying to evaluate X
which means it never has the need to r
Why does the following select statement succeed, instead of giving a
"no column error"? Is this a feature or a bug?
sqlite> select nonsensename and 0;
0
sqlite> .version
SQLite 3.8.1 2013-10-17 12:57:35 c78be6d786c19073b3a6730dfe3fb1be54f5657a
The select statement is not a subquery and has no fr
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