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2207/天天乐学答案/MySQL-1.md

@@ -335,10 +335,54 @@ 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
+CREATE VIEW v_scores AS
+SELECT c.cname, CEIL(AVG(sc.score)), MAX(sc.score), MIN(sc.score)
+FROM tb_students st, tb_scores sc, tb_courses c
+WHERE st.stuid = sc.student_id AND sc.course_id = c.cid
+GROUP BY c.cid;
 
+#9
+DELIMITER $$
+CREATE TRIGGER tri_updateAgeGroup
+BEFORE UPDATE ON tb_students
+FOR EACH ROW
+BEGIN
+	IF YEAR(NEW.birthday) BETWEEN 2004 AND 2024 THEN
+		SET NEW.age_group = '青年';
+	ELSEIF YEAR(NEW.birthday) BETWEEN 1984 AND 2003 THEN
+		SET NEW.age_group = '中年';
+	ELSEIF YEAR(NEW.birthday) < 1984 THEN
+		SET NEW.age_group = '老年';
+	END IF;
+END $$
+DELIMITER ;
 
+#10
+DELIMITER $$
+DROP PROCEDURE IF EXISTS pro_GetTopStudent;
+CREATE PROCEDURE pro_GetTopStudent(IN in_cid CHAR(11), OUT out_stuname VARCHAR(50))
+BEGIN 
+	SELECT st.stuname INTO out_stuname
+	FROM tb_students st, tb_scores sc
+	WHERE st.stuid = sc.student_id AND sc.course_id = in_cid
+	ORDER BY sc.score DESC
+	LIMIT 1;
+END $$
+DELIMITER ;
+
+CALL pro_GetTopStudent(1, @result);
+SELECT @result;
 ```
 
+
+