實(shí)例使用數(shù)據(jù)集：

SET NAMES utf8mb4;

SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------

-- Table structure for student

-- ----------------------------

DROP TABLE IF EXISTS `student`;

CREATE TABLE `student`? (

? `id` int(11) NOT NULL,

? `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,

? `age` int(11) NULL DEFAULT NULL,

? `addr` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,

? PRIMARY KEY (`id`) USING BTREE

) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------

-- Records of student

-- ----------------------------

INSERT INTO `student` VALUES (1, '張三', 16, '北京市通州區(qū)');

INSERT INTO `student` VALUES (2, '李四', 17, '河北石家莊');

INSERT INTO `student` VALUES (3, '李師師', 17, '河南洛陽');

INSERT INTO `student` VALUES (4, '杜甫', 18, '陜西西安');

INSERT INTO `student` VALUES (5, '高適', 16, '安徽福州');

INSERT INTO `student` VALUES (11, '李白', 11, '河北張家口');

SET FOREIGN_KEY_CHECKS = 1;

SET NAMES utf8mb4;

SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------

-- Table structure for core

-- ----------------------------

DROP TABLE IF EXISTS `core`;

CREATE TABLE `core`? (

? `id` int(11) NOT NULL,

? `sid` int(11) NULL DEFAULT NULL,

? `cname` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,

? `core` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,

? PRIMARY KEY (`id`) USING BTREE

) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------

-- Records of core

-- ----------------------------

INSERT INTO `core` VALUES (1, 1, '數(shù)學(xué)', '98');

INSERT INTO `core` VALUES (2, 1, '語文', '87');

INSERT INTO `core` VALUES (3, 1, '英語', '76');

INSERT INTO `core` VALUES (4, 2, '數(shù)學(xué)', '96');

INSERT INTO `core` VALUES (5, 2, '語文', '92');

INSERT INTO `core` VALUES (6, 2, '英語', '81');

INSERT INTO `core` VALUES (7, 3, '數(shù)學(xué)', '45');

INSERT INTO `core` VALUES (8, 3, '語文', '76');

INSERT INTO `core` VALUES (9, 7, '英語', '45');

INSERT INTO `core` VALUES (19, 8, '數(shù)學(xué)', '87');

SET FOREIGN_KEY_CHECKS = 1;

student表，單表數(shù)據(jù)情況：select * from student s

core表，單標(biāo)數(shù)據(jù)查詢情況：SELECT * FROM `core` c

多表，內(nèi)連接：select s.*,c.* from student s inner join `core` c on s.id = c.sid

左連接效果：

select s.*,c.* from student s left join `core` c on s.id = c.sid

有鏈接：select s.*,c.* from student s right join `core` c on s.id = c.sid

/*左外連接、右外連接跟左連接、右連接的結(jié)果一樣*/select s.*,c.* from student s left OUTER JOIN `core` c on s.id = c.sidselect s.*,c.* from student s right outer join `core` c on s.id = c.sid