[Zope-DB] Z SQL equivelant of MySQL's SQL_CALC_FOUND_ROWS?

Chris Withers chris at simplistix.co.uk
Mon Dec 5 02:42:09 EST 2005

Charlie Clark wrote:
>>>SELECT count(attribute) FROM relatiin WHERE condition
>>Ah, okay, now I gotcha...
>>>only returns 1 result so it's independent of LIMIT and result sets.
>>I wonder how the two methods compare efficiency-wise?

Yes, well, we're talking about MySQL specifically ;-)

> Maybe although I sometimes why MySQL does anything: the documentation seems 
> to imply that many decisions were sort of "let's do it like this": cf. 
> particularly the recommendations for writing queries with JOINs. Personally I 
> do not see it as valid SQL to predicate a query on "what was just asked". 

Sorry, not a lot of this paragraph made sense :-S

> Regarding the original question: if I know I am working with LIMITs or result 
> sets then this implies I don't want to know the total size of the results 
> beyound len(results).

Not so. Think of batches:

"Now showing Results 5 - 10 of 25"

But why not just return all the rows and only show 5 of them?

"Now showing Results 5 - 10 of 250000"


Yes, it'll likely be a slower query anyway, but I can assure you, Zope 
turning each of those rows into a Result object will be a LOT slower...



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