SQLite 3.27

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CREATE TABLE tablename (`id` INTEGER, `foo` TEXT);
✓
INSERT INTO tablename (`id`, `foo`) VALUES
  ('1', 'a'),
  ('2', 'b'),
  ('3', 'b'),
  ('4', 'b'),
  ('5', 'c'),
  ('6', 'a'),
  ('7', 'd');
✓
SELECT MIN(foo) = MAX(foo) AS result FROM tablename WHERE id IN (2, 3, 4);

result

1

SELECT MIN(foo) = MAX(foo) AS result FROM tablename WHERE id IN (2, 3);

result

1

SELECT MIN(foo) = MAX(foo) AS result FROM tablename WHERE id IN (1, 6);

result

1

SELECT MIN(foo) = MAX(foo) AS result FROM tablename WHERE id IN (5, 6);

result

0

SELECT MIN(foo) = MAX(foo) AS result FROM tablename WHERE id IN (1, 2);

result

0

SELECT COUNT(DISTINCT foo) = 1 AS result FROM tablename WHERE id IN (2, 3, 4);

result

1

SELECT COUNT(DISTINCT foo) = 1 AS result FROM tablename WHERE id IN (2, 3);

result

1

SELECT COUNT(DISTINCT foo) = 1 AS result FROM tablename WHERE id IN (1, 6);

result

1

SELECT COUNT(DISTINCT foo) = 1 AS result FROM tablename WHERE id IN (5, 6);

result

0

SELECT COUNT(DISTINCT foo) = 1 AS result FROM tablename WHERE id IN (1, 2);

result

0