文章目录

• • 原题题目
  • 代码实现（首刷自解）

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原题题目

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代码实现（首刷自解）

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# Write your MySQL query statement below
SELECT project_id,ROUND(SUM(experience_years) / COUNT(*),2) AS average_years
FROM project LEFT JOIN employee USING(employee_id)
GROUP BY project_id