Comments on: SQL SERVER – Simulate INNER JOIN using LEFT JOIN statement – Performance Analysis

By: Ashish Rajbanshi

Ashish Rajbanshi — Tue, 25 Aug 2009 23:46:31 +0000

does anyone know how to do the reverse? i.e. simulate left join using inner join?

By: Imran Mohammed

Imran Mohammed — Fri, 22 May 2009 05:05:53 +0000

@ Prem,

What do you mean by client system ?

In which format do you need to send data to client system.

If you want to provide data into excel or csv file, then try doing bcp, osql, dts or openquery. All these techniques are used to get data out of sql server in a desired form as you want.

It really does not matter if you want data from one table or multiple table, as long as you have script/query to populate data out of your sql database.

If this post does not answer your question, Please provide more info and please state your question clearly.

~ IM.

By: Prem

Prem — Fri, 22 May 2009 03:26:24 +0000

Hi Pinal,

Your blog regarding SQL server is Excellent.
I have a samll Issue, i need to migrate data from
Server to client system, Whether it may be a single table data or mulitple tables.
Please look into this and do favour

Regards
Prem

By: *tc

*tc — Wed, 12 Nov 2008 22:43:06 +0000

I often use, “WHERE 1 = 1″ just for convenience in adding or subtracting ANDs in a where clause.

That said, I also see no reason for esoteric questions like this in an interview.

Furthermore, while I agree that the Query Optimizer Engine helps to make less optimal queries run more optimally, it also enables bad coding practices. What happens if someone tries to port the same bad code to, heaven forbid, Oracle?

Sloppy coders also tend not to look at query plans.

I’m just sayin’ … *tc

By: John

John — Wed, 29 Oct 2008 07:26:49 +0000

Agree with Wes – why would you possibly want to simulate an inner join with an outer join?

By: Wes Brown

Wes Brown — Mon, 27 Oct 2008 01:04:24 +0000

While this is an interesting quirk of Sql Server I cannot imagine how it would be a useful question for an interview. What does it demonstrate other than a knowledge of useless sql constructs?

By: Eli Gassert

Eli Gassert — Sat, 25 Oct 2008 13:11:44 +0000

You can also use the same join clause and have your where be piy.ProductID IS NOT NULL

I’d be interested in knowing what the plan looks like for your SQL statement. Also, try doing the same JOINs on fields that aren’t indexes (like, say, product name, or product price) and see if you can get different results.

In more complicated situations, I’ve had to do similar things and had less success with the optimizer “figuring out” that it could do a cross join with inner join, so I’d be interested in hearing how the above tests play out in your test environment.

Cheers
-eli