i am learning this course, which says

By the end of this exercise, you'll be writing two queries back-to-back in a single script. You got this!

at the end of this exercise, I got following 2 pieces of sql code in one page.


SELECT country_code, size,
  CASE WHEN size > 50000000
            THEN 'large'
       WHEN size > 1000000
            THEN 'medium'
       ELSE 'small' END
       AS popsize_group
INTO pop_plus       
FROM populations
WHERE year = 2015;


Select name, continent, geosize_group, popsize_group
-- 1. From countries_plus (alias as c)
From countries_plus as c
  -- 2. Join to  pop_plus (alias as p)
  inner Join pop_plus as p
    -- 3. Match on country code
    on c.code = p.country_code
-- 4. Order the table    
order by geosize_group;

piece_2 is based on piece_1.

does "back-to-back" here mean piece_2 based on piece_1? or something else?


1 Answer 1


'Back to back' means the same as 'with no pause in between'. The second query is run directly after the first one.

This phrase is used to describe events that happen in close succession. It's often used in business settings for meetings that occur one after the other with no break in between them.

Thanks to a friend, here's another definition, from Wikipedia,that doesn't apply specifically to the question. This is a name for a type of house:

Back-to-backs share party walls on three of their four sides, with the front wall having the only door and windows.


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