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2208/天天乐学考试答案/MySQL练习（一）.md

@@ -335,15 +335,19 @@ FROM tb_students s
 WHERE TIMESTAMPDIFF(YEAR,s.birthday,'2023-12-01') BETWEEN 30 AND 40;
 
 #7
-
+SELECT st.stuname, st.gender, st.birthday, c.cname, sc.score,
+	IF(sc.score >= 90, '优秀', 
+	IF(sc.score >= 80, '良好', 
+	IF(sc.score >= 70, '中等', 
+	IF(sc.score >= 60, '及格', '不及格'))))
+FROM tb_students st, tb_scores sc, tb_courses c
+WHERE st.stuid = sc.student_id AND sc.course_id = c.cid
+ORDER BY sc.score DESC;
 
 #8
 
 
 ```
 
-### 第五套
 
-```sql
-```