「Puzzle55:競走馬の入賞回数」の編集履歴(バックアップ)一覧に戻る
CREATE
*SQL文
SELECT CASE WHEN count(N2.seq) = (SELECT (max(N1.seq) - min(N1.seq) +1) FROM Numbers N1) THEN 'has no missing number' ELSE 'exist missing number' END AS Numbers FROM Numbers N2;
seq ----- 2 3 5 7 8 14 20 の場合
numbers ---------------------- exist missing number
seq ----- 2 3 4 5 6 7 8 の場合
numbers ----------------------- has no missing number