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Databases

george spooner
george spooner
2,952 Points

Coding Challenge at the end of the Querying Relational Databases, JOIN challenge 2 of 5.. no matter what I put it always

SELECT Make.MakeName, Model.ModelName, Car.VIN, Car.StickerPrice FROM Car INNER JOIN Model ON Model.ModelID = Car.CarID INNER JOIN Make ON Make.MakeID = Car.CarID;

Why do I get the select MakeName, ModelName, VIN, StickerPrice error.. It returns the correct thing from the database..

1 Answer

Maciej Torbus
Maciej Torbus
8,137 Points

Hello George,

this task may be little tricky. Please take notice that the error doesn't always tell you everything. You are absolutely selecting the right colums, but please take a closer look at the result table.

Remember that you have to match (join) primary key from one table to corresponding foreign key in another table. CarID for example isn't foreign key it any of the tables, it's only primary key of Car table. While this might not be clear to see in result table, you should be able to notice second mistake in joining makes with models.

In your result table you probably have results like Chevy Focus or BMW Grand Cherokee. So you are selecting the right colums but they are not matched properly.

If you are not an expert on cars, you can play around and familiraze yourself with data and database schema somewhere in SQL Playgrounds. I remember that this car database has been somewhere before.

Hope I could help you and please remember that this topic isn't that easy, I still have problems with JOINs all the time. Feel free to ask me any question if this one was helpful!

george spooner
george spooner
2,952 Points

Thank you very much, your guidance worked. I am past that challenge now. I thought there might have been a bug but as you mentioned I wasn't matching things properly.

Much appreciated.

Maciej Torbus
Maciej Torbus
8,137 Points

I'm glad that I was able to help you out!