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Databases Querying Relational Databases Joining Table Data with SQL JOIN Queries

Tracy Cano
Tracy Cano
5,901 Points
Posted by Tracy Cano
Tracy Cano
5,901 Points

Can someone help me understand how to answer this question about outer joins?

Challenge Task 5 of 5 In a car database there is a Sale table with columns, SaleID, CarID, CustomerID, LocationID, SalesRepID, SaleAmount and SaleDate. The database also has a SalesRep table with columns, SalesRepID, FirstName, LastName, SSN, PhoneNumber, StreetAddress, City, State and ZipCode.

Show all SaleDate, SaleAmount, and SalesRep First and Last name from Sale and SalesRep. Make sure that all Sales appear in results even if there is no SalesRep associated to the sale.

1 Answer

Travis Alstrand
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Travis Alstrand
Data Analysis Techdegree Graduate 45,997 Points
Travis Alstrand
.a{fill-rule:evenodd;}techdegree seal-36
Travis Alstrand
Data Analysis Techdegree Graduate 45,997 Points

Hey there Tracy Cano ! :wave:

For this one, we need to utilize an OUTER JOIN to make sure we're showing all Sales, even if there is not an associated SalesRep for the row.

We'll want to specify what we want to select from both tables. I decided to put the Sale table on the "left" as it makes more sense in my head. Then LEFT OUTER JOIN the other table where the IDs match up.

I hope this makes sense! :smiley:

SELECT SaleDate, SaleAmount, FirstName, LastName
FROM Sale
LEFT OUTER JOIN SalesRep ON Sale.SalesRepID = SalesRep.SalesRepID