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mysql on、having、where、order by、group by的用法筆記

建立mysql的測試表

SET FOREIGN_KEY_CHECKS=0; -- 影響的是當前頁面,沒改變全域性的設定

-- ----------------------------
-- Table structure for dept
-- ----------------------------
DROP TABLE IF EXISTS `dept`;
CREATE TABLE `dept` (
  `deptno` int(2) NOT NULL,
  `dname` varchar(14) DEFAULT NULL,
  `loc` varchar(13) DEFAULT NULL,
  PRIMARY KEY (`deptno`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of dept
-- ----------------------------
INSERT INTO `dept` VALUES ('10', 'ACCOUNTING', 'NEW YORK');
INSERT INTO `dept` VALUES ('20', 'RESEARCH', 'DALLAS');
INSERT INTO `dept` VALUES ('30', 'SALES', 'CHICAGO');
INSERT INTO `dept` VALUES ('40', 'OPERATIONS', 'BOSTON');

-- ----------------------------
-- Table structure for emp
-- ----------------------------
DROP TABLE IF EXISTS `emp`;
CREATE TABLE `emp` (
  `empno` int(4) NOT NULL,
  `ename` varchar(10) DEFAULT NULL,
  `job` varchar(9) DEFAULT NULL,
  `mgr` int(4) DEFAULT NULL,
  `hiredate` date DEFAULT NULL,
  `sal` int(7) DEFAULT NULL,
  `comm` int(7) DEFAULT NULL,
  `deptno` int(2) DEFAULT NULL,
  PRIMARY KEY (`empno`),
  KEY `fk_deptno` (`deptno`),
  CONSTRAINT `fk_deptno` FOREIGN KEY (`deptno`) REFERENCES `dept` (`deptno`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of emp
-- ----------------------------
INSERT INTO `emp` VALUES ('7369', 'SMITH', 'CLERK', '7902', '1980-12-17', '800', null, '20');
INSERT INTO `emp` VALUES ('7499', 'ALLEN', 'SALESMAN', '7698', '1981-02-20', '1600', '300', '30');
INSERT INTO `emp` VALUES ('7521', 'WARD', 'SALESMAN', '7698', '1981-02-22', '1250', '500', '30');
INSERT INTO `emp` VALUES ('7566', 'JONES', 'MANAGER', '7839', '1981-04-02', '2975', null, '20');
INSERT INTO `emp` VALUES ('7654', 'MARTIN', 'SALESMAN', '7698', '1981-09-28', '1250', '1400', '30');
INSERT INTO `emp` VALUES ('7698', 'BLAKE', 'MANAGER', '7839', '1981-05-01', '2850', null, '30');
INSERT INTO `emp` VALUES ('7782', 'CLARK', 'MANAGER', '7839', '1981-06-09', '2450', null, '10');
INSERT INTO `emp` VALUES ('7788', 'SCOTT', 'ANALYST', '7566', '1987-04-19', '3000', null, '20');
INSERT INTO `emp` VALUES ('7839', 'KING', 'PRESIDENT', null, '1981-11-17', '5000', null, '10');
INSERT INTO `emp` VALUES ('7844', 'TURNER', 'SALESMAN', '7698', '1981-09-08', '1500', '0', '30');
INSERT INTO `emp` VALUES ('7876', 'ADAMS', 'CLERK', '7788', '1987-05-23', '1100', null, '20');
INSERT INTO `emp` VALUES ('7900', 'JAMES', 'CLERK', '7698', '1981-12-03', '950', null, '30');
INSERT INTO `emp` VALUES ('7902', 'FORD', 'ANALYST', '7566', '1981-12-03', '3000', null, '20');
INSERT INTO `emp` VALUES ('7934', 'MILLER', 'CLERK', '7782', '1982-01-23', '1300', null, '10');

-- ----------------------------
-- Table structure for salgrade
-- ----------------------------
DROP TABLE IF EXISTS `salgrade`;
CREATE TABLE `salgrade` (
  `grade` decimal(10,0) NOT NULL,
  `losal` decimal(10,0) DEFAULT NULL,
  `hisal` decimal(10,0) DEFAULT NULL,
  PRIMARY KEY (`grade`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of salgrade
-- ----------------------------
INSERT INTO `salgrade` VALUES ('1', '700', '1200');
INSERT INTO `salgrade` VALUES ('2', '1201', '1400');
INSERT INTO `salgrade` VALUES ('3', '1401', '2000');
INSERT INTO `salgrade` VALUES ('4', '2001', '3000');
INSERT INTO `salgrade` VALUES ('5', '3001', '9999');