Why is this part of the code needed?


#1


In this code I am not understanding why the text that is surrounded by "**" is needed. Why are we calling the table f? Then why are we saying "Where carrier = f.carrier"? All this code occurs in the same table so I don't understand the need for it. It is basically saying this column is equal to the same column, right?

SELECT id
FROM flights **AS f**
WHERE distance > (
 SELECT AVG(distance)
 FROM flights
 **WHERE carrier = f.carrier)**;


#2

In objective terms as I read it, f is a member of flights. f.carrier would then be that column in the flights table corresponding to row f It would imply an interative processs.


#3

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