Apple OA 面试真题解析：查找分配到多个项目的员工 ID

CoderPad provides a basic SQL sandbox with the following schema.

You can also use commands like show tables and desc <table_name>.

employees

• id (int)
• first_name (varchar)
• last_name (varchar)
• salary (int)
• department_id (int)

departments

• id (int)
• name (varchar)

projects

• id (int)
• title (varchar)
• start_date (date)
• end_date (date)
• budget (int)

employees_projects

• project_id (int)
• employee_id (int)

Identify the employee IDs that have more than 1 project.

这道题考察 SQL 的分组统计与 HAVING 过滤：需要从 employees_projects 关联表中按 employee_id 分组，统计每个员工对应的项目数量，并筛选出项目数大于 1 的员工 ID。关键点在于不要直接用 WHERE 过滤聚合结果，而应使用 GROUP BY + HAVING COUNT(*) > 1 来完成。