Consider the following database. Employee has a unique eid, name, age and salary
ID: 3733346 • Letter: C
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. 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 doesn’t 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
Write SQL queries for the following. Submit all queries.
1.Find the total salary of all employees.
2.Select the name and salary of the employee with the highest salary.
3.Select the department name and their respective manager name.
4.Select the employee names and their department names of the employees who work less than 50% of the time in that department.
5.Select the employee name and no of departments each employee works for.
6.Select the employee names with salary greater than average salary of all employees.
7.Select the department names with no manager assigned yet.
8.Select the employee names who work for more than 1 department.
9.Select the employee names and their manager names (keep in mind, one employee works for multiple departments so they will have multiple managers).
10.Select the name and salary of the employee with the second highest salary.
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
Explanation / Answer
Solution:
The first four subparts have been answered as per Chegg guidelines, please repost others.
I suggest you post them as a set of 4 and you will get better and faster response.
1)
SELECT SUM(salary) FROM Employees
Explanation:
SUM() is an aggregate function which will total the salary column and give us the desired result.
2)
SELECT ename, salary FROM Emp WHERE salary = MAX(salary)
Explanation:
MAX() is an aggregate function which will Maximum the salary column and give us the desired result.
3)
SELECT dname, managerid FROM Dept
4)
SELECT ename, dname FROM Emp INNER JOIN Works ON Emp.eid= Works.eid INNER JOIN Dept ON Dept.did= Works.did WHERE pct_time=50
I hope this helps if you find any problem. Please comment below. Don't forget to give a thumbs up if you liked it. :)
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