Simple Query I Need.....

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Simple Query I Need.....

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Ryan Naude Ten Centuries Points: 1369 More actions · Answer 1

SELECT EXP(SUM(LOG(SID))) FROM #t

I don't understand how this actually works. We getting the float value of all the numbers and then converting it into an exponential value. Sorry guys, looks past my ignorance for a second. Are we then saying that the sum of two natural logarithm values is equal to multiplying them? Snap, this could be extremely handy. I would have gone the dynamic SQL route probably, I am curious though to see the dynamic SQL that Sandy used in the first attempt. Reading forums is enlightening. Thanks guys.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 2

It's a property of logarithms.

Edit: My maths stinks. So out of practice.

e^{(ln(x) + ln(y))} = x * y for all values of x and y

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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Johan Bijnens SSC Guru Points: 135374 More actions · Answer 3

the mighty BOL states :

Remarks EXP
The constant e (2.718281…), is the base of natural logarithms.
The exponent of a number is the constant e raised to the power of the number.
For example EXP(1.0) = e^1.0 = 2.71828182845905 and EXP(10) = e^10 = 22026.4657948067.
The exponential of the natural logarithm of a number is the number itself: EXP (LOG (n)) = n.
And the natural logarithm of the exponential of a number is the number itself: LOG (EXP (n)) = n.
Remarks LOG
The constant e (2.71828182845905…) is the base of natural logarithms.
The base of natural logarithms is the constant e (2.71828182845905…).
LOG ( e ) = 1.0.
The natural logarithm of the exponential of a number is the number itself: LOG( EXP( n ) ) = n.
And the exponential of the natural logarithm of a number is the number itself: EXP( LOG( n ) ) = n.

I knew there must have been a purpose for all those hours of math +20 years ago :w00t:

Johan

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Ryan Naude Ten Centuries Points: 1369 More actions · Answer 4

Crisis, this is getting confusing, yet inspires me to go and find more of these wierd, but usefull, functions. Thanks for the insight guys.

Grant Fritchey SSC Guru Points: 398909 More actions · Answer 5

Hey Sandy,

Sorry I'm late to the game, but everything Jeff said goes double for me. 😀

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Matt Miller (4) SSC Guru Points: 124210 More actions · Answer 6

So - anyone up for a good round of sine/cosine/tangent/arctengent?

Remember: SOHCAHTOA...

Ahhh - high-school math....Nope - I still don't remember most of it@

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Jeff Moden SSC Guru Points: 1004403 More actions · Answer 7

Sandy (1/17/2008)
Hey sqluser,
Thanks, It is working...
Jeff,
Actually I asked about this post...
" http://www.sqlservercentral.com/Forums/Topic444141-338-1.aspx "
Jeff,
-------------
Sandy learned nothing about what Sandy was supposed to learn... except how to cheat. Great job, Pal!
he he he...lolz:hehe:
Cheers!
Sandy.

So... I see you've adopted the answer that was not the intent of the question... you've learned nothing except, obviously, how to type "he he he". You've missed a prime learning opportunity by cheating and still getting the wrong answer for the question posed by your instructor... question was meant for you to study recurrsion... not to get the mathematically correct equation.

You have no idea what you're doing to yourself...

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
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Create a Tally Function (fnTally)

IN_Sandeep SSCertifiable Points: 6259 More actions · Answer 8

Hi Jeff,:hehe:

Thanks for your suggestion.

I will follow this..

Thanks for the same...

No more.....he he he..lolz...;):P:w00t::cool::hehe:

Cheers!

Sandy.

--

Jeff Moden SSC Guru Points: 1004403 More actions · Answer 9

We'll see... when you figure out the correct answer for the real question being asked, post it here.

--Jeff Moden

RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
First step towards the paradigm shift of writing Set Based code:
________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

Change is inevitable... Change for the better is not.

Helpful Links:
How to post code problems
How to Post Performance Problems
Create a Tally Function (fnTally)