Best way of getting Empty Result Set

There were discussions on this over a year ago, I recall. But I don't
recall a consensus emerging.

What is the most efficient way of running a query to produce an empty
resultset?

Select * from MyTable
Where
....???

-d

True = false?
1=0?

"Chris" <nospam@nospam.com> wrote in message
news:46ee69de$1@nexus-vkpb9bih5.Nexus.local...
> True = false?
> 1=0?

Yep, I wonder if there is something even more efficient than that.

On a table with about 30 columns and 1000 records this takes 328 msecs.

It'll do, but...

-d

Dennis Landi wrote:
> "Chris" <nospam@nospam.com> wrote in message
> news:46ee69de$1@nexus-vkpb9bih5.Nexus.local...
>> True = false? 1=0?
>
> Yep, I wonder if there is something even more efficient than that.
>
> On a table with about 30 columns and 1000 records this takes 328
> msecs.
>
> It'll do, but...
>
> -d

Turn off request live since it causes it to evaluate the condition
for each record. Using TOP 0 will also prevent the query from
being live.

#L-
SELECT * FROM SOMETABLE WHERE 0=1;

or

SELECT TOP 0 * FROM SOMETABLE;

--
Brian Evans [NDX]
Ottawa, ON, CANADA
GMT-5

Brian Evans [NDX] wrote:
> Dennis Landi wrote:
>> "Chris" <nospam@nospam.com> wrote in message
>> news:46ee69de$1@nexus-vkpb9bih5.Nexus.local...
>>> True = false? 1=0?
>>
>> Yep, I wonder if there is something even more efficient than that.
>>
>> On a table with about 30 columns and 1000 records this takes 328
>> msecs.
>>
>> It'll do, but...
>>
>> -d
>
> Turn off request live since it causes it to evaluate the condition
> for each record. Using TOP 0 will also prevent the query from being
> live.
>
> #L- SELECT * FROM SOMETABLE WHERE 0=1;
>
> or
>
> SELECT TOP 0 * FROM SOMETABLE;
>

Opps, #L is for log. The request live query is an option
not a statement switch.

--
Brian Evans [NDX]
Ottawa, ON, CANADA
GMT-5

"Brian Evans [NDX]" <bevanson@rogers.com> wrote in message
news:46ee7ca8@nexus-vkpb9bih5.Nexus.local...

>> Turn off request live since it causes it to evaluate the condition for
>> each record. Using TOP 0 will also prevent the query from being
>> live.
>>
>> #L- SELECT * FROM SOMETABLE WHERE 0=1;
>>
>> or
>>
>> SELECT TOP 0 * FROM SOMETABLE;
>>
>
> Opps, #L is for log. The request live query is an option
> not a statement switch.

Thanks Brian.

"Dennis Landi" <nada@nada.com> wrote in message
news:46ee6b09$1@nexus-vkpb9bih5.Nexus.local...
>
> "Chris" <nospam@nospam.com> wrote in message
> news:46ee69de$1@nexus-vkpb9bih5.Nexus.local...
>> True = false?
>> 1=0?
>
> Yep, I wonder if there is something even more efficient than that.
>
> On a table with about 30 columns and 1000 records this takes 328 msecs.
>
> It'll do, but...
>
> -d
>

Seems odd, I've just tested against my address server table with 1.7m rows,
30 (ish) columns over my wireless network and it completes is 78ms. I guess
the 'request live' really does slow it down....yep, just tried and it takes
forever.

> Seems odd, I've just tested against my address server table with 1.7m rows,
> 30 (ish) columns over my wireless network and it completes is 78ms. I guess
> the 'request live' really does slow it down....yep, just tried and it takes
> forever.

Request live is essentially working like a server side sql filter.

--

Hannes Danzl [NexusDB Developer]
Newsgroup archive at http://www.tamaracka.com/search.htm

Chris wrote:

> True = false?
> 1=0?

Would
WHERE True=False

actually be faster than
WHERE False

? I use the latter all the time. I even created a routine to change any
SQL statement
SELECT
....
WHERE .....

into
SELECT
....
WHERE FALSE AND ....

(I needed this just to get the output column names & types, and NO DATA)


--
Thanks,
Hans Hasenack (Netherlands)

"Dennis Landi" <nada@nada.com> wrote in message
news:46ee645c$1@nexus-vkpb9bih5.Nexus.local...
> There were discussions on this over a year ago, I recall. But I don't
> recall a consensus emerging.
>
> What is the most efficient way of running a query to produce an empty
> resultset?
>
> Select * from MyTable
> Where
> ...???
>

Anyone found faster than:

SELECT * FROM "MyTable" where 1 = -1

???

-d