Can someone please explain me this code? Why do we need dep_date here?What do we mean by Group By 1,2,3?Why do we need a?
AVG(a.flight_distance) AS average_distance
SUM(distance) AS flight_distance
GROUP BY 1,2,3
GROUP BY 1,2
ORDER BY 1,2;
<do not remove the three backticks above>
I also wanted to ask why is it necessary to make an alias name for columns in sub queries?
those “column alias names” are then used as header in your selection-list…
i also wanted to ask the same thing…why do we need dep-date in the subquery?
Maybe this helps
4. Non-Correlated Subqueries III
found with google search
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