inner join can be written in four ways? is it true

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inner join can be written in four ways? is it true

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learning_grsql
Posting Yak Master

230 Posts

Posted - 2012-08-28 : 10:54:06

I used to write a inner join query in four ways and so far I have always assumed all four will give same output.

But I'm not sure if that is really true or it has any unknown effects.


First :

Update C set C.field1 = D.field1 from tblhelptable D
join tblmaintable C on C.field2 = D.field2

Second :
Update C set C.field1 = D.field1 from tblmaintable C 
join tblhelptable D on C.field2 = D.field2

Third :
Update C set C.field1 = D.field1 from tblhelptable D
join tblmaintable C on D.field2 = C.field2

Fourth :
Second :
Update C set C.field1 = D.field1 from tblmaintable C 
join tblhelptable D on D.field2 = C.field2

sunitabeck
Master Smack Fu Yak Hacker

5155 Posts

Posted - 2012-08-28 : 10:58:27

Identical. http://www.youtube.com/watch?v=i2nuPVTU4Z4

learning_grsql
Posting Yak Master

230 Posts

Posted - 2012-08-28 : 11:04:15

@sunitabeck.....thanks but i don't find any information related sql in your link.

so you mean it can be used alternatively?

sunitabeck
Master Smack Fu Yak Hacker

5155 Posts

Posted - 2012-08-28 : 11:10:36

quote:
Originally posted by learning_grsql

@sunitabeck.....thanks but i don't find any information related sql in your link.

so you mean it can be used alternatively?

Sorry, I was trying to be funny, but guess not. That link is really a link to scene from the movie "My Cousin Vinny".

Yes, the four updates are identical. Should be logically and physically be identical as far as I know.

learning_grsql
Posting Yak Master

230 Posts

Posted - 2012-08-28 : 13:29:30

Oh sorry then. I'm not so good in English so I could not understand what you were trying to do and I thought by mistake you posted incorrect link....BTW: Many thanks for your useful replies in many threads..

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