经典sql题(九)SQL 查询详细指南总结二
示例 综合上一章内容,编写一个示例 SQL 查询: SELECT DISTINCT a.user_id, COALESCE(b.amount, 0) AS amount FROM users a LEFT JOIN transactions b ON a.user_id b.user_id WHERE a.status active GROUP BY a.user_id HAVING COUNT(b.transaction…
2024-10-07