程序用到的表和數據
CREATE TABLE tb_dic_class (
class_id int(11) DEFAULT NULL,
class_name varchar(20) DEFAULT NULL,
createtime datetime DEFAULT 'CURRENT_TIMESTAMP',
modifytime datetime DEFAULT 'CURRENT_TIMESTAMP'
)
ENGINE = INNODB
AVG_ROW_LENGTH = 5461
CHARACTER SET utf8
COLLATE utf8_general_ci;
CREATE TABLE tb_students (
id int(11) NOT NULL,
student_name varchar(30) DEFAULT NULL,
class_id int(11) DEFAULT NULL,
createtime datetime DEFAULT 'CURRENT_TIMESTAMP',
modifytime datetime DEFAULT 'CURRENT_TIMESTAMP',
PRIMARY KEY (id)
)
ENGINE = INNODB
AVG_ROW_LENGTH = 5461
CHARACTER SET utf8
COLLATE utf8_general_ci;
INSERT INTO tb_dic_class(class_id, class_name, createtime, modifytime) VALUES
(1, '一班', now(), now());
INSERT INTO tb_dic_class(class_id, class_name, createtime, modifytime) VALUES
(2, '二班', now(), now());
INSERT INTO tb_dic_class(class_id, class_name, createtime, modifytime) VALUES
(3, '三班', now(), now());
SET NAMES 'utf8';
INSERT INTO tb_students(id, student_name, class_id, createtime, modifytime) VALUES
(10, '張三', 1, now(), now());
INSERT INTO tb_students(id, student_name, class_id, createtime, modifytime) VALUES
(20, '李四', 1, now(), now());
INSERT INTO tb_students(id, student_name, class_id, createtime, modifytime) VALUES
(30, '王五', 3, now(), now());
1.loop-loop嵌套
CREATE PROCEDURE hxl.sp_loop_loop()
BEGIN
DECLARE l_class_id int;
DECLARE l_class_name varchar(20);
DECLARE l_student_id int;
DECLARE l_student_name varchar(20);
DECLARE done int;
DECLARE cur_out CURSOR FOR
SELECT
class_id,class_name
FROM tb_dic_class;
DECLARE cur_inner CURSOR FOR
SELECT
ID,
student_name
FROM tb_students
WHERE class_id = l_class_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cur_out;
out_loop:
LOOP
FETCH cur_out INTO l_class_id,l_class_name;
IF done = 1 THEN
LEAVE out_loop;
END IF;
open cur_inner;
inner_loop:LOOP
FETCH cur_inner INTO l_student_id,l_student_name;
IF done = 1 THEN
LEAVE inner_loop;
end IF;
SET @output_string= CONCAT('班級編碼:',l_class_id,',班級名稱:',l_class_name,',學生編號:',l_student_id,',學生名稱:',l_student_name);
SELECT @output_string;
end LOOP inner_loop;
CLOSE cur_inner;
SET done=0;
END LOOP out_loop;
CLOSE cur_out;
END
2.loop-while嵌套
CREATE PROCEDURE sp_loop_while()
BEGIN DECLARE l_class_id INT;
DECLARE l_class_name VARCHAR(20);
DECLARE l_student_id INT;
DECLARE l_student_name VARCHAR(20);
DECLARE done INT;
DECLARE cur_out CURSOR FOR
SELECT class_id
, class_name
FROM
tb_dic_class;
DECLARE cur_inner CURSOR FOR
SELECT ID
, student_name
FROM
tb_students
WHERE
class_id = l_class_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cur_out;
out_loop:
LOOP
FETCH cur_out INTO l_class_id, l_class_name;
IF done = 1 THEN
LEAVE out_loop;
END IF;
OPEN cur_inner;
SET done = 0; /* 內層循環控制*/
FETCH cur_inner INTO l_student_id, l_student_name;
WHILE done <> 1
DO
SET @output_string = concat('班級編碼:', l_class_id, ',班級名稱:', l_class_name, ',學生編號:', l_student_id, ',學生名稱:', l_student_name);
SELECT @output_string;
FETCH cur_inner INTO l_student_id, l_student_name;
END WHILE;
CLOSE cur_inner;
SET done = 0; /* 外層循環控制*/
END LOOP out_loop;
CLOSE cur_out;
END
3.loop-repeat嵌套
CREATE PROCEDURE sp_loop_repeat()
BEGIN DECLARE l_class_id INT;
DECLARE l_class_name VARCHAR(20);
DECLARE l_student_id INT;
DECLARE l_student_name VARCHAR(20);
DECLARE done INT;
DECLARE cur_out CURSOR FOR
SELECT class_id
, class_name
FROM
tb_dic_class;
DECLARE cur_inner CURSOR FOR
SELECT ID
, student_name
FROM
tb_students
WHERE
class_id = l_class_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cur_out;
out_loop:
LOOP
FETCH cur_out INTO l_class_id, l_class_name;
IF done = 1 THEN
LEAVE out_loop;
END IF;
OPEN cur_inner;
SET done = 0;
REPEAT
FETCH cur_inner INTO l_student_id, l_student_name;
if done <> 1 then
SET @output_string = concat('班級編碼:', l_class_id, ',班級名稱:', l_class_name, ',學生編號:', l_student_id, ',學生名稱:', l_student_name);
SELECT @output_string;
end if;
UNTIL done
END REPEAT;
CLOSE cur_inner;
SET done = 0; /* 外層循環控制*/
END LOOP out_loop;
CLOSE cur_out;
END
