SQL一道问题求解。很简单的!在线等!
来源:百度知道 编辑:UC知道 时间:2024/04/29 15:32:32
问题是下面有3个table分别是:
Aircraft (aID, aName, cruisingRange)
Certified (eID, aID)
Employees (eID, eName, Salary)
现在是要写一个SQL query找出aircraft的名字aName,但是这架aircraft的飞行员(employee)的工资(salary)要在$80,000以上.
谢谢大家。在线等!
我写的query是
SELECT ANAME FROM AIRCRAFT
WHERE AID = CERTIFIED.AID
AND CERTIFIED.EID = EMPLOYEES.EID
AND EMPLOYEES.SALARY > $80,000;
但是老师说的all the tables of concerned attributes need to specify in the FROM clause. There is only one table specified in your SQL code.
希望大家帮忙改一下!!谢谢!!
Aircraft (aID, aName, cruisingRange)
Certified (eID, aID)
Employees (eID, eName, Salary)
现在是要写一个SQL query找出aircraft的名字aName,但是这架aircraft的飞行员(employee)的工资(salary)要在$80,000以上.
谢谢大家。在线等!
我写的query是
SELECT ANAME FROM AIRCRAFT
WHERE AID = CERTIFIED.AID
AND CERTIFIED.EID = EMPLOYEES.EID
AND EMPLOYEES.SALARY > $80,000;
但是老师说的all the tables of concerned attributes need to specify in the FROM clause. There is only one table specified in your SQL code.
希望大家帮忙改一下!!谢谢!!
SELECT ANAME FROM AIRCRAFT,CERTIFIED,EMPLOYEES
WHERE AIRCRAFT.AID = CERTIFIED.AID
AND CERTIFIED.EID = EMPLOYEES.EID
AND EMPLOYEES.SALARY > $80,000;
上面一句话的意思大概是所有连接的表都要在FROM项里显示出来,也就是
SELECT ANAME FROM 这一项
你查询的字段包含在三个表里面,所以在这后面三个表都要列出来。
还有要查询显示的项也要放在Selected和From中间 可以改为
SELECT ANAME,EMPLOYEES.SALARY FROM AIRCRAFT,Certified,Employees
WHERE AID = CERTIFIED.AID
AND CERTIFIED.EID = EMPLOYEES.EID
where EMPLOYEES.SALARY > $80,000;
这是一个等值内连接