NOT (A or B) = (NOT A) and (NOT B)

抽象例

SELECT * FROM table WHERE NOT (A or B);
同じ
SELECT * FROM table WHERE (NOT A) and (NOT B);

具体例

HAVING
  NOT (
    COUNT(DISTINCT a.id) > 1
      OR COUNT(DISTINCT b.id) > 1
  )

リファクタ

HAVING
  COUNT(DISTINCT a.id) <= 1
  AND COUNT(DISTINCT b.id) <= 1

NOT (A and B) = (NOT A) or (NOT B)

抽象例

SELECT * FROM table WHERE NOT (A and B);
SELECT * FROM table WHERE (NOT A) or (NOT B);

具体例

  HAVING
    NOT (
      COUNT(DISTINCT a.id) > 1
        AND COUNT(DISTINCT b.id) > 1
    )

リファクタ

HAVING
  COUNT(DISTINCT a.id) <= 1
    OR COUNT(DISTINCT b.id) <= 1