Welcome to ecourse.org: the Information Infrastructure for Education in the information age! This system allows instructors from any school or college (including home schools and training programs) to teach either onsite or online courses . It allows students to manage all their ongoing school works and past academic records at one location.
Our mission is to redefine the model of learning and re-engineer its process by providing innovative administrative and instructional technologies. Click here for our beliefs.
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Could another species someday replace us as Earth's dominant intelligent life and, if so, which species?
(641 Week 9 Outline) (by Liping Liu) Review:
1. Find employees who make more than all managers
2. Find the maximum average salaries of all departments
3. Find the number of columns in EMP table
4... more >>
(641 Week 7 Outline) (by Liping Liu) Warm-Up Queries:
Find the employment year of each employee
Find the departments in Dallas
Find the salesmen who were hired after 1980
--Find menagers whose name ends with M
select enamefrom empwhere job = 'MANAGER' and ename like '%M';
--Give salesman 100 commission
update empset comm = comm + 100where job = 'SALESMAN';
--handle missing values
upate empset comm = 0where comm is null;
select 12*sal + commfrom empgroup by empno;
--use nvl(comm, 0)
update empset comm = nvl(comm, 0) + 100where job = 'SALESMAN';
Lecture 1: Intermediate SQL Programming: Join
implicit join (outer and inner), Explicit Join: inner join, left join, right join, full outer join (or cross join)
Find all the employees located in Dallas
Find all employees and their associated departments
Find all departments and their associated employees
Explicit Joins
Just like + operation in arithmetics to combine two tables, may be used in parentheses for nested combination of more than two tables
Syntax: TableA join TableB on (criterion to join)
three explicit Join types: left, right, inner
Equivalent to implicit joins (e... more >>
This system is designed and developed by Professor Liping Liu with financial support from Southern Illinois University at Carbondale. It evolved from a prior version called CourseWeb (for courses prior to Year 2000) and UXTEND.COM and www.e-course.org.
