| 用途 | 结果排序 |
|---|---|
| 语法 | ORDER BY 列1 [ASC|DESC], 列2 … |
| 增强 | ORDER BY FIELD() / 表达式 / 8.0 的降序索引 |
常用示例
常用示例
SELECT id, qty FROM orders ORDER BY qty DESC;
SELECT id FROM orders ORDER BY status, created_at DESC LIMIT 50;
SELECT id FROM orders ORDER BY FIELD(status,'pending','paid','shipped');配合索引
配合索引
ALTER TABLE orders ADD INDEX idx_status_created (status, created_at DESC);排序 + LIMIT 是分页标配；执行计划里出现 Using filesort 意味着可能发生了额外排序。