how grab text before a "-" character in a join

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how grab text before a "-" character in a join

spikenology-616218

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Points: 391
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March 2, 2011 at 8:07 am

#247548

I am doing a select query, and trying to join in another table where the common field in one table looks like "1234" and the other table has a dash and extra numbers like "1234-01". My join statement is this -
left outer join orders o on o.orderno = d.jobno
What I want to do is grab the value of d.jobno to the left of the dash ("-") character. Can I do this with charindex or something?
Thanks!

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Sean Lange SSC Guru Points: 286590 More actions · Answer 1

Yeap.

declare @OddBallKey varchar(10) = '1234-01'

select SUBSTRING(@OddBallKey, 0, charindex('-', @OddBallKey, 0))

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Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

spikenology-616218 Old Hand Points: 391 More actions · Answer 2

Thanks for the quick response. The problem is, I am doing a join on a table that has numbers like

1000-01

1001-01

1002-01

etc.

and I want to join to a table where the values are correspondingly

1000

1001

1002

So, I hoped I could just grab in my left outer join statement something to grab the value of the field prior to the dash...if that makes sense. If there were all the same length, I could do use the left and a number, but that isn't the case.

Sean Lange SSC Guru Points: 286590 More actions · Answer 3

That is what i showed you. 😀

Try this to see if it makes it more clear.

select *

from table A

join table b on a.ID = SUBSTRING(b.IDFieldWithExtra, 0, charindex('-', b.IDFieldWithExtra, 0))

_______________________________________________________________

Need help? Help us help you.

Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

Need to split a string? Try Jeff Modens splitter http://www.sqlservercentral.com/articles/Tally+Table/72993/.

Cross Tabs and Pivots, Part 1 – Converting Rows to Columns - http://www.sqlservercentral.com/articles/T-SQL/63681/
Cross Tabs and Pivots, Part 2 - Dynamic Cross Tabs - http://www.sqlservercentral.com/articles/Crosstab/65048/
Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

drew.allen SSC Guru Points: 76985 More actions · Answer 4

Another option is to use the LIKE operator. I don't know which will perform better.

SELECT *

FROM TableA

INNER JOIN TableB

ON TableA.ID LIKE Cast(TableB.ID as varchar(11)) + '%'

This assumes that the '1001-01' from TableA is stored as a string and the 1001 from TableB is stored as an int. If they are both strings, you don't need the CAST.

Drew

J. Drew Allen
Business Intelligence Analyst
Philadelphia, PA

spikenology-616218 Old Hand Points: 391 More actions · Answer 5

spikenology-616218

Old Hand

Points: 391

March 2, 2011 at 9:04 am

#1293568

I've got - thanks for the awesome assistance!

Jeff Moden SSC Guru Points: 1004356 More actions · Answer 6

drew.allen (3/2/2011)
Another option is to use the LIKE operator. I don't know which will perform better.
SELECT *
FROM TableA
INNER JOIN TableB
ON TableA.ID LIKE Cast(TableB.ID as varchar(11)) + '%'
This assumes that the '1001-01' from TableA is stored as a string and the 1001 from TableB is stored as an int. If they are both strings, you don't need the CAST.
Drew

Oh... be careful, now. What's going to happen if one string is 1001-01 and another is 10011-01?

--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)

Sean Lange SSC Guru Points: 286590 More actions · Answer 7

Jeff Moden (3/2/2011)
drew.allen (3/2/2011)
Another option is to use the LIKE operator. I don't know which will perform better.
SELECT *
FROM TableA
INNER JOIN TableB
ON TableA.ID LIKE Cast(TableB.ID as varchar(11)) + '%'
This assumes that the '1001-01' from TableA is stored as a string and the 1001 from TableB is stored as an int. If they are both strings, you don't need the CAST.
Drew
Oh... be careful, now. What's going to happen if one string is 1001-01 and another is 10011-01?

And of course performance was pretty much tossed out the window when the join forces a full scan anyway.

_______________________________________________________________

Need help? Help us help you.

Read the article at http://www.sqlservercentral.com/articles/Best+Practices/61537/ for best practices on asking questions.

Need to split a string? Try Jeff Modens splitter http://www.sqlservercentral.com/articles/Tally+Table/72993/.

Cross Tabs and Pivots, Part 1 – Converting Rows to Columns - http://www.sqlservercentral.com/articles/T-SQL/63681/
Cross Tabs and Pivots, Part 2 - Dynamic Cross Tabs - http://www.sqlservercentral.com/articles/Crosstab/65048/
Understanding and Using APPLY (Part 1) - http://www.sqlservercentral.com/articles/APPLY/69953/
Understanding and Using APPLY (Part 2) - http://www.sqlservercentral.com/articles/APPLY/69954/

drew.allen SSC Guru Points: 76985 More actions · Answer 8

Jeff Moden (3/2/2011)
drew.allen (3/2/2011)
Another option is to use the LIKE operator. I don't know which will perform better.
SELECT *
FROM TableA
INNER JOIN TableB
ON TableA.ID LIKE Cast(TableB.ID as varchar(11)) + '%'
This assumes that the '1001-01' from TableA is stored as a string and the 1001 from TableB is stored as an int. If they are both strings, you don't need the CAST.
Drew
Oh... be careful, now. What's going to happen if one string is 1001-01 and another is 10011-01?

Yes, I thought about that after posting, but haven't had a chance to revise the post. You should concatenate '-%' instead of just '%'.

As for the join causing a full scan, I think that both the Cast and the Substring will have the same effect. If the IDs are both stored as char, the LIKE method may be able to use an index.

Drew

J. Drew Allen
Business Intelligence Analyst
Philadelphia, PA