-- 學(xué)生信息表
DROP TABLE IF EXISTS t_student;
CREATE TABLE `t_student` (
  `id` BIGINT(12) NOT NULL AUTO_INCREMENT COMMENT '主鍵',
  `code` VARCHAR(10) NOT NULL COMMENT '學(xué)號(hào)',
  `name` VARCHAR(20) NOT NULL COMMENT '姓名',
  `age` INT(2) NOT NULL COMMENT '年齡',
  `gender` CHAR(1) NOT NULL COMMENT '性別（M：男，F(xiàn)：女）',
  PRIMARY KEY (`id`),
  UNIQUE KEY UK_STUDENT (`code`)
) CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

-- 學(xué)生成績(jī)表
DROP TABLE IF EXISTS t_achievement;
CREATE TABLE `t_achievement` (
  `id` BIGINT(12) NOT NULL AUTO_INCREMENT COMMENT '主鍵',
  `year` INT(4) NOT NULL COMMENT '學(xué)年',
  `subject` CHAR(2) NOT NULL COMMENT '科目（01：語(yǔ)文，02：數(shù)學(xué)，03：英語(yǔ)）',
  `score` INT(3) NOT NULL COMMENT '得分',
  `student_id` BIGINT(12) NOT NULL COMMENT '所屬學(xué)生id',
  PRIMARY KEY (`id`) 
) CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

-- 成績(jī)匯總表
DROP TABLE IF EXISTS t_achievement_report;
CREATE TABLE `t_achievement_report` (
  `id` BIGINT(12) NOT NULL AUTO_INCREMENT COMMENT '主鍵',
  `student_id` BIGINT(12) NOT NULL COMMENT '學(xué)生id',
  `year` INT(4) NOT NULL COMMENT '學(xué)年',
  `total_score` INT(4) NOT NULL COMMENT '總分',
  `avg_score` DECIMAL(4,2) NOT NULL COMMENT '平均分',
  PRIMARY KEY (`id`) 
) CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

INSERT INTO t_student(id, CODE, NAME, age, gender) VALUES
(1, '2022010101', '小張', 18, 'M'),
(2, '2022010102', '小李', 18, 'F'),
(3, '2022010103', '小明', 18, 'M');
INSERT INTO t_achievement(YEAR, SUBJECT, score, student_id) VALUES
(2022, '01', 80, 1),
(2022, '02', 85, 1),
(2022, '03', 90, 1),
(2022, '01', 60, 2),
(2022, '02', 90, 2),
(2022, '03', 98, 2),
(2022, '01', 75, 3),
(2022, '02', 100, 3),
(2022, '03', 85, 3);

-- 如果存儲(chǔ)過(guò)程存在，先刪除存儲(chǔ)過(guò)程
DROP PROCEDURE IF EXISTS statistics_achievement;
DELIMITER $$
-- 定義存儲(chǔ)過(guò)程
CREATE PROCEDURE statistics_achievement()
BEGIN
        -- 定義變量記錄循環(huán)處理是否完成
	DECLARE done BOOLEAN DEFAULT FALSE;
        -- 定義變量傳遞學(xué)生id
	DECLARE studentid BIGINT(12);
	-- 定義游標(biāo)
	DECLARE cursor_student CURSOR FOR SELECT id FROM t_student;
	-- 定義CONTINUE HANDLER，當(dāng)循環(huán)結(jié)束時(shí) done=true
	DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET done=TRUE;
	-- 打開(kāi)游標(biāo)
	OPEN cursor_student;
	-- 重復(fù)遍歷
	REPEAT 
		-- 每次讀取一次游標(biāo)
		FETCH cursor_student INTO studentid;
                -- 計(jì)算總分、平均分插入?yún)R總表
		INSERT INTO t_achievement_report(student_id, `YEAR`, total_score, avg_score)
		SELECT studentid, `YEAR`, SUM(score), ROUND(SUM(score) / 3, 2) FROM t_achievement t1 WHERE student_id = studentid AND NOT EXISTS(
			SELECT 1 FROM t_achievement_report t2 WHERE student_id = studentid AND t1.year = t2.year
		) GROUP BY `YEAR`;
	-- 結(jié)束循環(huán)，意思是等到done=true時(shí)，結(jié)束循環(huán)REPEAT
	UNTIL done END REPEAT;
	-- 查詢結(jié)果，僅會(huì)展示查出的最后一條
	SELECT studentid;
	-- 關(guān)閉游標(biāo)
	CLOSE cursor_student;
END$$
DELIMITER ;

-- 執(zhí)行存儲(chǔ)過(guò)程
CALL statistics_achievement();