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maxsubrat
Active User
Joined: 27 Feb 2008 Posts: 110 Location: india
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Hi, Here is the details. I want to resolve this thru an query.
I have 2 tables :
table a-- emp barcode
123 555
124 666
table b-- emp1 barcode1
123 999
124 888
If the column emp = emp1 for the 1st row, then update the barcode with the barcode1. for exp:
The updated table for the 1st row will be as per below.
table a-- emp barcode
123 999
124 666
table b-- emp1 barcode1
123 999
124 888
like that it will continue o update whenever it matches the emp with emp1.
Thanks in advance. |
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dbzTHEdinosauer
Global Moderator
Joined: 20 Oct 2006 Posts: 6966 Location: porcelain throne
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what are the indexes for the two tables?
can there be duplicates in table 1 for emp a?
i.e.:
Code: |
emp barcode
123 12344556
123 12344555
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same applies to table b.
if there is only one row per emp in both tables,
why not
Code: |
UPDATE TABA A
SET BARCODE = (SELECT BARCODE
FROM TABB B
WHERE A.EMPLNO = B.EMPLNO)
WHERE A.EMPLNO IN (SELECT EMPLNO
FROM TABB )
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GuyC
Senior Member
Joined: 11 Aug 2009 Posts: 1281 Location: Belgium
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or
Code: |
UPDATE TABA A
SET BARCODE = (SELECT BARCODE
FROM TABB B
WHERE A.EMPLNO = B.EMPLNO)
WHERE exists ( select EMPLNO
FROM TABB B where A.EMPLNO = B.EMPLNO)
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same thing, different performance. Which one is the best depends on several things. Just try them both. |
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