Cross Apply --reducing the number of combinations

Question

Cross Apply --reducing the number of combinations

rhmohamed

SSC Rookie

Points: 30
More actions
March 13, 2014 at 8:57 am

#289413

Hi,
I have issue with ny cross apply.I'm currently using to combine values from 2 fields.
example:
fields A = 1,2,3
fields B = X,Z
using the cross apply give me that results :
1,X
1,Z
2,X
2,Z
3,X
3,Z
But would like to keep only combinations with new components.Example :
1,X
1,Z
2,Null
3,Null,
Thanks for your help

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Jeff Moden SSC Guru Points: 1004706 More actions · Answer 1

rhmohamed (3/13/2014)
Hi,
I have issue with ny cross apply.I'm currently using to combine values from 2 fields.
example:
fields A = 1,2,3
fields B = X,Z
using the cross apply give me that results :
1,X
1,Z
2,X
2,Z
3,X
3,Z
But would like to keep only combinations with new components.Example :
1,X
1,Z
2,Null
3,Null,
Thanks for your help

So, when would 2 and 3 EVER have any "new components" that weren't already present in 1?

--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)

rhmohamed SSC Rookie Points: 30 More actions · Answer 2

Hi,

That's totally correct.

was almost there by adding a distinct to my query and adding the PK.but seems not totaly correct.

Best regards

ChrisM@Work SSC Guru Points: 186127 More actions · Answer 3

rhmohamed (3/14/2014)
Hi,
That's totally correct.
was almost there by adding a distinct to my query and adding the PK.but seems not totaly correct.
Best regards

What makes 2 and 3 different from 1?

How do you identify "new components"?

There's insufficient information to offer any useful answer.

^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

For fast, accurate and documented assistance in answering your questions, please read this article.
Understanding and using APPLY, (I) and (II) Paul White
Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden