Ikechukwu Arum3,495 Points
related to the subquery challenge using the "IN" Keyword
In a car database there is a Model table with columns, ModelID, MakeID and ModelName and a Car table with columns, CarID, ModelID, VIN, ModelYear and StickerPrice. Use a subquery along with IN to list all the Model Names with a Sticker Price greater than $30000
SELECT ModelName FROM MODEL WHERE ModelID IN (SELECT ModelID FROM CAR WHERE stickerPrice >30000);
I was able to solve this problem using the code above. however I am confused as to why I am not able subquery the "Model" table instead. Below are the codes I've tried:
The code below give me errors because of "modelname"
SELECT ModelName, ModelID, stickerPrice FROM car WHERE stickerPrice >30000 AND ModelID IN(SELECT ModelID From Model);
The code below gives me error because of the alias.
SELECT M.ModelName, ModelID, stickerPrice FROM car WHERE stickerPrice >30000 AND ModelID IN(SELECT ModelID From Model) AS M;
Can anyone please explain if it can be done and how?
Steven Parker177,495 Points
The second example has two issues:
FROM carthe "car" database has no "ModelName" field
ModelID IN (SELECT ModelID from Model)will always be true, so it won't filter anything
And for the last example, there's also two issues:
- for "M" to be a data source for the SELECT, it must appear in a FROM or JOIN clause
- you can't give an alias to a subquery in a WHERE clause