SQL JOINS的7种结构（SQL语法以mysql为例）

一、建表语句

部门表：

DROP TABLE IF EXISTS `tbl_dept`;
CREATE TABLE `tbl_dept` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`deptName` varchar(30) DEFAULT NULL,
`locAdd` varchar(40) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of tbl_dept
-- ----------------------------
INSERT INTO `tbl_dept` VALUES ('1', 'RD', '11');
INSERT INTO `tbl_dept` VALUES ('2', 'HR', '12');
INSERT INTO `tbl_dept` VALUES ('3', 'MK', '13');
INSERT INTO `tbl_dept` VALUES ('4', 'MIS', '14');
INSERT INTO `tbl_dept` VALUES ('5', 'FD', '15');

员工表：

DROP TABLE IF EXISTS `tbl_emp`;
CREATE TABLE `tbl_emp` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(30) DEFAULT NULL,
`deptId` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `fk_dept_id` (`deptId`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of tbl_emp
-- ----------------------------
INSERT INTO `tbl_emp` VALUES ('1', 'Z3', '1');
INSERT INTO `tbl_emp` VALUES ('2', 'Z4', '1');
INSERT INTO `tbl_emp` VALUES ('3', 'Z5', '1');
INSERT INTO `tbl_emp` VALUES ('4', 'W5', '2');
INSERT INTO `tbl_emp` VALUES ('5', 'W6', '2');
INSERT INTO `tbl_emp` VALUES ('6', 'S7', '3');
INSERT INTO `tbl_emp` VALUES ('7', 'S8', '4');
INSERT INTO `tbl_emp` VALUES ('8', 'S9', '51');