SQLite 3.27

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select sqlite_version();


sqlite_version()


3.27.2


CREATE TABLE flight
(
  class TEXT NOT NULL CHECK (class IN ('Business', 'Economy', 'First')),
  iata  TEXT NOT NULL,
  cnt   INTEGER NOT NULL
)
INSERT INTO flight VALUES
('Business', 'DL', 2),
('Business', 'SN', 2),
('Economy',  'SN', 2),
('First',    'BA', 2),
('Economy',  'BA', 1),
('Economy',  'DL', 1),
('First',    'SN', 1);
SELECT
  class, iata, MAX(cnt)
FROM flight
WHERE class = 'First'
GROUP BY class, iata
LIMIT 1;


class
iata
MAX(cnt)


First
BA
2


INSERT INTO flight VALUES
('First', 'EI', 2);
SELECT
  class, iata, MAX(cnt)
FROM flight
WHERE class = 'First'
GROUP BY class, iata
LIMIT 1;


class
iata
MAX(cnt)


First
BA
2


SELECT
  class, iata, MAX(cnt) AS c
FROM flight
WHERE class = 'First'
GROUP BY class, iata
HAVING MAX(cnt) = (
             SELECT 
               MAX(cnt) 
             FROM flight 
             WHERE class = 'First' 
           );


class
iata
c


First
BA
2

First
EI
2


SELECT 
  *,
  DENSE_RANK() OVER (PARTITION BY class ORDER BY cnt DESC) AS dr
FROM flight
WHERE class = 'First'
ORDER BY dr ASC;


class
iata
cnt
dr


First
BA
2
1

First
EI
2
1

First
SN
1
2


SELECT
  *
FROM
(
  SELECT 
    *,
    DENSE_RANK() OVER (PARTITION BY class ORDER BY cnt DESC) AS dr
  FROM flight
  WHERE class = 'First'
  ORDER BY dr ASC
) AS t
WHERE dr = 1;


class
iata
cnt
dr


First
BA
2
1

First
EI
2
1


SELECT
 class    AS "Class",
 SUM(cnt) AS "Total"
FROM flight
GROUP BY class;


Class
Total


Business
4

Economy
4

First
5


SELECT SUM(cnt) FROM flight;


SUM(cnt)


13


SELECT
 class    AS "Class",
 SUM(cnt) AS "Total",
 ROUND(SUM(cnt) * 1.0/(SELECT SUM(cnt) FROM flight) * 100) AS "Percentage"
FROM flight
GROUP BY class;


Class
Total
Percentage


Business
4
31

Economy
4
31

First
5
38