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2207/天天乐学答案/合卷-1.md

@@ -227,4 +227,71 @@ GROUP BY h.hid;
 
 
 
-### MySQL-2
+### MySQL-2
+
+```sql
+#1添加主键
+ALTER TABLE tb_student ADD PRIMARY KEY(student_id);
+
+#2设置默认值
+ALTER TABLE tb_student ALTER gender SET DEFAULT '男';
+
+#3 插入记录
+INSERT INTO tb_student()
+VALUES(10025, '张三', DEFAULT, '2012-10-01', 1001);
+
+#4 更新记录
+UPDATE tb_teacher t
+SET t.teacher_age = 36
+WHERE t.teacher_name = '王老师';
+
+#5 tj11
+SELECT MAX(t.age)
+FROM tb_teacher t;
+
+#6 tj12
+SELECT c.class_name, s.student_name, s.gender
+FROM tb_teacher t, tb_student s, tb_class C
+where s.class_id = c.class_id AND c.teacher_id = t.teacher_id;
+
+#7 视图
+CREATE VIEW v_teacher AS
+SELECT c.class_name, t.teacher_name, COUNT(*)
+FROM tb_teacher t, tb_student s, tb_class C
+where s.class_id = c.class_id AND c.teacher_id = t.teacher_id
+GROUP BY c.class_id;
+
+#8
+DELIMITER $$
+DROP TRIGGER IF EXISTS tri_updateTeacherAge;
+CREATE TRIGGER tri_updateTeacherAge
+BEFORE UPDATE ON tb_teacher
+FOR EACH ROW
+BEGIN
+		IF NEW.teacher_age < 30 THEN
+			SET NEW.age = '青年';
+		ELSEIF NEW.teacher_age < 50 THEN
+			SET NEW.age = '中年';
+		ELSE
+			SET NEW.age = '老年';
+		END IF;
+END $$
+DELIMITER ;
+
+#9
+DELIMITER $$
+DROP PROCEDURE IF EXISTS Pro_GetOldClassStudent;
+CREATE PROCEDURE Pro_GetOldClassStudent(IN in_class_id INT, OUT out_student_name VARCHAR(50))
+BEGIN
+	SELECT s.student_name INTO out_student_name
+	FROM tb_student s, tb_class c
+	WHERE s.class_id = c.class_id AND c.class_id = in_class_id
+	ORDER BY s.birthday
+	LIMIT 1;
+END $$
+DELIMITER ;
+
+CALL Pro_GetOldClassStudent(1001, @result);
+SELECT @result;
+```
+