📝 よく使うSQL命令一覧
| 命令 | 説明 | 例 |
|---|---|---|
SELECT | データを取得 | SELECT name FROM users |
WHERE | 条件で絞り込む | WHERE age >= 20 |
ORDER BY | 並び替え | ORDER BY age DESC |
LIMIT | 取得件数を制限 | LIMIT 10 |
COUNT | 件数を数える | SELECT COUNT(*) |
SUM / AVG | 合計・平均 | SELECT AVG(salary) |
GROUP BY | グループ化 | GROUP BY department |
HAVING | 集計後の絞り込み | HAVING COUNT(*) > 3 |
INNER JOIN | テーブル結合 | JOIN t2 ON t1.id = t2.id |
LIKE | 部分一致検索 | WHERE name LIKE '山%' |
