我需要計算薪水高於平均水平的部門的僱員人數。MySQL - 錯誤1054(42S22):'having clause'中的未知列'sal'
我的員工表:
+------+--------+-----------+------+------------+------+------+--------+
| eno | ename | job | mgr | hiredate | sal | comm | deptno |
+------+--------+-----------+------+------------+------+------+--------+
| 7369 | smith | clerk | 7902 | 1980-12-17 | 800 | NULL | 20 |
| 7499 | allen | salesman | 7698 | 1981-02-20 | 1600 | 300 | 30 |
| 7521 | ward | salesman | 7698 | 1981-02-22 | 1250 | 500 | 30 |
| 7566 | jones | manager | 7839 | 1981-04-02 | 2975 | NULL | 20 |
| 7654 | martin | salesman | 7698 | 1981-10-28 | 1250 | 1400 | 30 |
| 7698 | blake | manager | 7839 | 1981-05-01 | 2850 | NULL | 30 |
| 7782 | clark | manager | 7839 | 1981-06-09 | 2450 | NULL | 10 |
| 7788 | scott | analyst | 7566 | 1982-12-09 | 3000 | NULL | 20 |
| 7839 | king | president | NULL | 1981-11-17 | 5000 | NULL | 10 |
| 7844 | turner | salesman | 7698 | 1981-10-08 | 1500 | NULL | 30 |
| 7876 | adams | clerk | 7788 | 1983-01-12 | 1100 | NULL | 20 |
| 7900 | james | clerk | 7698 | 1981-12-03 | 950 | NULL | 30 |
| 7902 | ford | analyst | 7566 | 1981-12-03 | 3000 | NULL | 20 |
| 7934 | miller | clerk | 7782 | 1982-01-23 | 1300 | NULL | 10 |
+------+--------+-----------+------+------------+------+------+--------+
我試圖做的查詢是
select deptno, count(*) from emp group by deptno having sal > avg(sal)
,這時候我得到的錯誤。
我想這也查詢:
select deptno, count(*), avg(sal) from emp group by deptno
這基本上是除了沒有having子句中的相同,它按預期工作。
-
select deptno, count(*) from emp where sal > avg(sal) group by deptno
此查詢引發以下錯誤:
ERROR 1111 (HY000): Invalid use of group function
-
select deptno, count(*) from emp group by deptno where sal > avg(sal)
這Ø NE使用不正確的語法:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'where sal > avg(sal)' at line 1
-
爲什麼會出現這個錯誤?這將是執行此查詢的正確方法?提前致謝。
插入腳本:
SET SQL_MODE="NO_AUTO_VALUE_ON_ZERO";
SET time_zone = "+00:00";
/*!40101 SET @[email protected]@CHARACTER_SET_CLIENT */;
/*!40101 SET @[email protected]@CHARACTER_SET_RESULTS */;
/*!40101 SET @[email protected]@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
CREATE TABLE IF NOT EXISTS `emp` (
`eno` int(11) NOT NULL AUTO_INCREMENT,
`ename` varchar(30) DEFAULT NULL,
`job` varchar(30) DEFAULT NULL,
`mgr` int(11) DEFAULT NULL,
`hiredate` date DEFAULT NULL,
`sal` int(11) DEFAULT NULL,
`comm` int(11) DEFAULT NULL,
`deptno` int(11) DEFAULT NULL,
PRIMARY KEY (`eno`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=10000 ;
INSERT INTO `emp` (`eno`, `ename`, `job`, `mgr`, `hiredate`, `sal`, `comm`, `deptno`) VALUES
(7369, 'smith', 'clerk', 7902, '1980-12-17', 800, NULL, 20),
(7499, 'allen', 'salesman', 7698, '1981-02-20', 1600, 300, 30),
(7521, 'ward', 'salesman', 7698, '1981-02-22', 1250, 500, 30),
(7566, 'jones', 'manager', 7839, '1981-04-02', 2975, NULL, 20),
(7654, 'martin', 'salesman', 7698, '1981-10-28', 1250, 1400, 30),
(7698, 'blake', 'manager', 7839, '1981-05-01', 2850, NULL, 30),
(7782, 'clark', 'manager', 7839, '1981-06-09', 2450, NULL, 10),
(7788, 'scott', 'analyst', 7566, '1982-12-09', 3000, NULL, 20),
(7839, 'king', 'president', NULL, '1981-11-17', 5000, NULL, 10),
(7844, 'turner', 'salesman', 7698, '1981-10-08', 1500, NULL, 30),
(7876, 'adams', 'clerk', 7788, '1983-01-12', 1100, NULL, 20),
(7900, 'james', 'clerk', 7698, '1981-12-03', 950, NULL, 30),
(7902, 'ford', 'analyst', 7566, '1981-12-03', 3000, NULL, 20),
(7934, 'miller', 'clerk', 7782, '1982-01-23', 1300, NULL, 10);
/*!40101 SET [email protected]_CHARACTER_SET_CLIENT */;
/*!40101 SET [email protected]_CHARACTER_SET_RESULTS */;
/*!40101 SET [email protected]_COLLATION_CONNECTION */;
什麼是你的MySQL版本? – Jocelyn
https://dev.mysql.com/doc/refman/5.7/en/group-by-handling.html看看 – Naruto
@Jocelyn我正在使用MySQL 5.5.24。 – SoKeT