What is the purpose of subquery and nesting a subq

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What is the purpose of subquery and nesting a subq

Author

Topic

rv498
Yak Posting Veteran

60 Posts

Posted - 2014-03-04 : 17:30:38

Can you show me an example of subquery nesting? Thanks

rv498
Yak Posting Veteran

60 Posts

Posted - 2014-03-04 : 18:43:21

So I came up with the code below, is this a legit nested subquery?
It returns no rows but I get no error messages.

SELECT DISTINCT c.ResellerName
FROM dbo.DimReseller c JOIN dbo.FactResellerSales e
ON e.ResellerKey = c.ResellerKey WHERE ProductLine IN
(SELECT ProductLine
FROM dbo.DimProduct
WHERE StandardCost IN
(SELECT ProductStandardCost
FROM dbo.FactInternetSales
WHERE ProductStandardCost > 1000))

jackv
Master Smack Fu Yak Hacker

2179 Posts

Posted - 2014-03-05 : 01:47:52

A Subquery is a query within another SQL query , embedded within the WHERE clause. So , yes it looks like a legit query. There are some subquery rules which need to be followed

They are useful for completing more complex queries

Jack Vamvas
--------------------
http://www.sqlserver-dba.com

rv498
Yak Posting Veteran

60 Posts

Posted - 2014-03-05 : 08:27:06

Thanks jacky, can you take a look at above code and see if it's qualified as nested subquery?

MIK_2008
Master Smack Fu Yak Hacker

1054 Posts

Posted - 2014-03-05 : 08:37:04

I believe so - a query with a subquery.

Cheers
MIK

rv498
Yak Posting Veteran

60 Posts

Posted - 2014-03-05 : 08:41:27

Thanks MIK

MIK_2008
Master Smack Fu Yak Hacker

1054 Posts

Posted - 2014-03-05 : 09:44:18

you're welcome!

Cheers
MIK

maunishq
Yak Posting Veteran

71 Posts

Posted - 2014-03-05 : 10:26:27

It returns error message when there is error in your syntax or when the object you referring does not exist in that particular schema/db/table. It pulls 0 rows means your query is right but there is nothing that satisfy your logic.

=======================
Not an Expert, Just a learner.
!_(M)_!

rv498
Yak Posting Veteran

60 Posts

Posted - 2014-03-05 : 10:45:44

thanks maunishq

jackv
Master Smack Fu Yak Hacker

2179 Posts

Posted - 2014-03-07 : 01:48:09

quote:
Originally posted by rv498

Thanks jacky, can you take a look at above code and see if it's qualified as nested subquery?

Yes ,it does as a nested query - based on the definition I posted

Jack Vamvas
--------------------
http://www.sqlserver-dba.com

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