mysql实现多表连查，查找出用户没有加入的课程数据

/*
 Navicat Premium Data Transfer

 Source Server         : root@localhost
 Source Server Type    : MySQL
 Source Server Version : 50726
 Source Host           : localhost:3306
 Source Schema         : study

 Target Server Type    : MySQL
 Target Server Version : 50726
 File Encoding         : 65001

 Date: 11/05/2022 16:17:52
*/

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for course
-- ----------------------------
DROP TABLE IF EXISTS `course`;
CREATE TABLE `course`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = MyISAM AUTO_INCREMENT = 5 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of course
-- ----------------------------
INSERT INTO `course` VALUES (1, '语文');
INSERT INTO `course` VALUES (2, '数学');
INSERT INTO `course` VALUES (3, '英语');
INSERT INTO `course` VALUES (4, '计算机');

-- ----------------------------
-- Table structure for study_course
-- ----------------------------
DROP TABLE IF EXISTS `study_course`;
CREATE TABLE `study_course`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `course_id` int(11) NULL DEFAULT NULL,
  `user_id` int(11) NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = MyISAM AUTO_INCREMENT = 3 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Fixed;

-- ----------------------------
-- Records of study_course
-- ----------------------------
INSERT INTO `study_course` VALUES (1, 1, 1);
INSERT INTO `study_course` VALUES (2, 2, 3);

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = MyISAM AUTO_INCREMENT = 3 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES (1, '张三');
INSERT INTO `user` VALUES (2, '李四');

SET FOREIGN_KEY_CHECKS = 1;

SELECT
    *
FROM
    course
WHERE
    id NOT IN (
    SELECT
        course_id
    FROM
        study_course
WHERE
    user_id = ( SELECT id FROM `user` WHERE `name` = '张三' ))