CAST placement in SQL

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#1

Hey there! qq about CAST and where this goes when executing an aggregation? Why In the below query does CAST not belong in the 4th column on both c.urban_pop as well? I wanted tot type this (CAST(c.urban_pop AS FLOAT) / CAST(f.population AS float))?

Here is the correct query:
SELECT
f.name AS country,
c.urban_pop,
f.population AS total_pop,
(c.urban_pop / CAST(f.population AS float)) AS urban_pct
FROM facts as f
INNER JOIN (SELECT
facts_id,
SUM(population) urban_pop
FROM cities
GROUP BY 1) AS c ON c.facts_id = f.id
WHERE urban_pct > .5
ORDER BY urban_pct ASC;

#2

There is an existing question similar to yours that should help - Why is CAST placed in denominator ? Why not placed in both numerator and denominator?

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