mysql INNER/LEFT/RIGHT JOIN区别

 1、创建table

DROP TABLE IF EXISTS `tab_id_index`;
CREATE TABLE `tab_id_index` (
  `id` int(11) NOT NULL DEFAULT '0',
  `name` varchar(10) DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of tab_id_index
-- ----------------------------
INSERT INTO `tab_id_index` VALUES ('1', '3', '12');
INSERT INTO `tab_id_index` VALUES ('2', '3', '12');
INSERT INTO `tab_id_index` VALUES ('3', '3', '12');
INSERT INTO `tab_id_index` VALUES ('5', '4', '14');

DROP TABLE IF EXISTS `tab_no_index`;
CREATE TABLE `tab_no_index` (
  `id` int(11) NOT NULL DEFAULT '0',
  `name` varchar(10) DEFAULT NULL,
  `age` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of tab_no_index
-- ----------------------------
INSERT INTO `tab_no_index` VALUES ('1', '1', '12');
INSERT INTO `tab_no_index` VALUES ('2', '1', '12');
INSERT INTO `tab_no_index` VALUES ('3', '3', '12');
INSERT INTO `tab_no_index` VALUES ('4', '6', '14');

2、sql查询

select * from tab_id_index a,tab_no_index b where a.id = b.id;

同：

select * from tab_id_index a INNER JOIN tab_no_index b ON a.id = b.id;

select * from tab_id_index a LEFT JOIN tab_no_index b ON a.id = b.id;

同：

select * from tab_id_index a LEFT OUTER JOIN tab_no_index b ON a.id = b.id;

select * from tab_id_index a RIGHT JOIN tab_no_index b ON a.id = b.id;

同：

select * from tab_id_index a RIGHT OUTER JOIN tab_no_index b ON a.id = b.id;