[NewToPCGuy]

I have two customer tables from two different sources. Both tables contain the same customers but both have there own unique Id's for these customers. Being that these tables are managed by two separate companies, I cannot alter these tables in any way.

I want to build a cross reference table to link these customers together. The problem is that both tables often list the same customer several times. Example:

Customer_Table_1
Cust_ID Cust_Name
123567 St. Johns
23456 Saint Johns


Customer_Table_2
Cust_ID Cust_Name
98765 St. Johns
45678 St John


The only way I can think to link these two tables would be as follows:

Cust_Id_Xref_Table
Cust_ID_1 Table_ID New_Cust_Id
123567 1 1000
23456 1 1000
98765 2 1000
45678 2 1000


These three columns would make the new PK of the new table.

Considering that i cannot clean the original tables, this is the only solution that I can come up with.

Does anyone know of a better way to handle this situation?

Thanks in advance

[coderitr]

Welcome to TSG.

What you've come up with is, IMO the best way to handle this.

[ddockstader]

Welcome to Relational Databases and the world according to C. J. Date. What you describe is the way to handle many-to-many relationships. Now, you can speed up any queries by indexing that resulting table, but that's the textbook answer.

[NewToPCGuy]

Many thanks for the confirmation!