Question
Consider the following database. Employee has a unique eid, name, age and salary. Department has a unique did, name and an employee as a manager.
Consider the following database. Employee has a unique eid, name, age and salary. Department has a unique did, name and an employee as a manager. A department may or may not have a manager assigned. An employee can work for multiple departments. The pct_time in Works table is the percentage of time an employee works for a department. The salary of the employees is fixed and is not based on pct_time or the deparments they work in.
Emp (eid: INT(11), ename: VARCHAR(50), age: INT(11), salary: FLOAT)
Works (eid: INT(11), did: INT(11), pct_time: INT(11))
Dept (did: INT(11), dname: VARCHAR(50, managerid: INT(11))
Constraints
eid is primary key for Emp table and cannot be NULL
did is primary key for Dept table and cannot be NULL
eid and did are foreign keys referencing to Emp and Dept tables respectively in Works table. combination of eid and did is the primary key or works table.
managerid is foreign key referencing to Emp table and can have NULL values if the department doesnt have a manager assigned.
Sample values.
Emp
eid | ename | age | salary |
1001 | Georgi Facello | 34 | 45000.00 |
1002 | Parto Bamford | 28 | 34000.00 |
1003 | Christian Koblick | 42 | 55000.00 |
1004 | Saniya Peac | 24 | 28000.00 |
Dept
did | dname | managerid |
d001 | Marketing | 1003 |
d002 | Finance | 1002 |
d003 | Information Security | NULL |
Works
eid | did | pct_time |
1001 | d001 | 60 |
1002 | d002 | 100 |
1003 | d001 | 100 |
1001 | d003 | 40 |
1004 | d003 | 50 |
1004 | d002 | 50 |
1. Write SQL queries for the following. Submit all queries. (5 points each)
A) Select the employee name and no of departments each employee works for.
B) Select the employee names with salary greater than average salary of all employees.
C) Select the department names with no manager assigned yet.
D) Select the employee names who work for more than 1 department.
E) Select the employee names and their manager names (keep in mind, one employee works for multiple departments so they will have multiple managers).
F) Select the name and salary of the employee with the second highest salary.
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