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 what does this alias do?		  New Topic  Reply to Topic
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tracmonali
Starting Member

16 Posts
Posted - 05/19/2012 :  10:02:04  Show Profile  Reply with Quote
can somebody help me understand how is this alias for the select stmt diff than a temp table? would putting in a temp table be an optimal solution?
Scenario1:
select * from tabl1
inner join (
select * from table 3
inner join table 4 on table3.col1 = table4.col1) AliasName
on AliasName.col4 = tabl1.col1

Scenario2
Create table #tempAliasName (col1, col2, col3, col4)
insert into #tempAliasName
(select * from table 3
inner join table 4 on table3.col1 = table4.col1)

select * from tabl1
inner join #tempAliasName
on #tempAliasName.col4 = tabl1.col1

Please help me understand the diff between 2 scenarios (wrt optimization, good querying practice, overhead on server) if any?

SwePeso
Patron Saint of Lost Yaks

Sweden
29138 Posts
Posted - 05/19/2012 :  13:00:44  Show Profile  Visit SwePeso's Homepage  Reply with Quote 
SELECT		*
FROM		dbo.Table1 AS t1
INNER JOIN	dbo.Table3 AS t3 ON t2.Col4 = t1.Col1
INNER JOIN	dbo.Table4 AS t4 ON t4.Col1 = t3.Col1


N 56°04'39.26"
E 12°55'05.63"
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tracmonali
Starting Member

16 Posts
Posted - 05/20/2012 :  10:45:03  Show Profile  Reply with Quote
quote:
Originally posted by SwePeso

SELECT		*
FROM		dbo.Table1 AS t1
INNER JOIN	dbo.Table3 AS t3 ON t2.Col4 = t1.Col1
INNER JOIN	dbo.Table4 AS t4 ON t4.Col1 = t3.Col1


N 56°04'39.26"
E 12°55'05.63"


there is no selection from table2??????
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visakh16
Very Important crosS Applying yaK Herder

India
47173 Posts
Posted - 05/20/2012 :  11:23:43  Show Profile  Reply with Quote
quote:
Originally posted by tracmonali

quote:
Originally posted by SwePeso

SELECT		*
FROM		dbo.Table1 AS t1
INNER JOIN	dbo.Table3 AS t3 ON t2.Col4 = t1.Col1
INNER JOIN	dbo.Table4 AS t4 ON t4.Col1 = t3.Col1


N 56°04'39.26"
E 12°55'05.63"


there is no selection from table2??????



there's no table2 in your example

------------------------------------------------------------------------------------------------------
SQL Server MVP
http://visakhm.blogspot.com/
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