howdy ya'll, I'm relatively new to SQL and taking a course that uses NASA data from the cassini space mission.

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There's a query I'm seeing that kiiiind of makes sense, but I want to make sure I'm understanding what it's doing under the hood.

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For reference, there's a table called teams, that has 14 distinct team names and a team id as a primary key. There is also a table called master_plan that has a team column with the same names but repeated a bunch because there's ~64k entries.

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The nested select in the following code is what's got me scratching my head:

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insert into plans(start, title, team_id, description)
select
    start_time_utc::timestamp,
    title,
    (select id from teams where name = csvs.master_plan.team),
    description
    from csvs.master_plan
    where target = 'Enceladus' and title is not null;

is the nested select basically iterating through each row in the master_plan and then using the smaller table called teams as a lookup table like in excel to pull the id? like literally going row by row by row by row etc etc. I get that its creating a column of the id, but I guess the logic has me somewhat confused.

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If I switched it to:

(select id from teams where csvs.master_plan.team = name)

would that work? to me that makes sense as in each row of master plan's team column uses the teams table to look up the corresponding id.