Select pairs from one table not in another?

Question

Select pairs from one table not in another?

andy.gear

SSC-Addicted

Points: 493
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June 10, 2009 at 7:37 am

#133150

So I have two tables that have two fields that are the same. How do I find pairs in one table that are not in another table? For Example:
Table1
Cust#, CustName
1,Cust1
2,Cust2
3,Cust3
Table2
Cust#,CustName
1,Cust1
4,Cust4
I want to write a query that compares Table1 to Table2 and results in:
4,Cust4

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Lowell SSC Guru Points: 323507 More actions · Answer 1

andy.gear (6/10/2009)
So I have two tables that have two fields that are the same. How do I find pairs in one table that are not in another table? For Example:
Table1
Cust#, CustName
1,Cust1
2,Cust2
3,Cust3
Table2
Cust#,CustName
1,Cust1
4,Cust4
I want to write a query that compares Table1 to Table2 and results in:
4,Cust4

a simple LEFT join should do it:

SELECT * FROM Table1

LEFT OUTER JOIN Table2

ON Table1.[Cust#] = Table2.[Cust#]

AND Table1.[CustName] = Table2.[CustName]

WHERE Table2.[CustName] IS NULL --not in Table2

--OR

--WHERE Table1.[CustName] IS NULL --not in Table1

Lowell

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Mark Cowne One Orange Chip Points: 26945 More actions · Answer 2

Using EXCEPT will give you pairs in Table1 that aren't in Table2

SELECT [Cust#],CustName FROM Table1

EXCEPT

SELECT [Cust#],CustName FROM Table2

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