exercise 04 sql i - · exercise 04 –sql i. systems ... tpch database schema 10 exercise 3...
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Data Modelling and Databases FS 2018
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Exercise 04 – SQL I
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Employee database schema
departments(dept_no:string, dept_name:string)
dept_emp(emp_no:int, dept_no:string, from_date:date, to_date:date)
dept_manager(emp_no:int, dept_no:string,
from_date:date, to_date:date)
employees(emp_no:int, birth_date:date, first_name:string,
last_name:string, gender:enum, hire_date:date)
salaries(emp_no:int, salary:int, from_date:date, to_date:date)
title(emp_no:int, title:string, from_date:date, to_date:date)
2
Exercise 1 – Employee Dataset
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Average salaries per department
3
Exercise 1 – Employee Dataset
Wrong projection
Missing filters
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Salaries
4
Exercise 1 – Employee Dataset
Average of current
salaries per department
Department managers
Managers with higher salary than average
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Employees names
5
Exercise 1 – Employee Dataset
Wrong index
It only matches the first letter
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First employees
6
Exercise 1 – Employee Dataset
SELECT
e.first_name, e.last_name
FROM employees e
ORDER BY e.hire_date, e.last_name ASC
LIMIT 10
SELECT * FROM (
) AS res
ORDER BY last_name ASC
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1998
7
Exercise 1 – Employee Dataset
FROM salaries s, dept_emp de, departments dp
SELECT
dp.dept_no AS deptnumber,
dp.dept_name AS deptname,
avg(salary) AS avg_salary
WHERE
de.emp_no = s.emp_no
AND dp.dept_no = de.dept_no
AND date_part(’year’, s.from_date) = 1988
GROUP BY dp.dept_no
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Current managers
8
Exercise 1 – Employee Dataset
FROM employees e
SELECT
e.first_name, e.last_name, t.title,
d.dept_name, s.salary
JOIN dept_manager dm ON dm.emp_no = e.emp_no
JOIN departments d ON dm.dept_no = d.dept_no
JOIN titles t ON t.emp_no = e.emp_no
JOIN salaries s ON s.emp_no = e.emp_no
WHERE
dm.to_date > NOW()
AND t.to_date > NOW()
AND s.to_date > NOW()
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Exercise 2 – ZVV Dataset
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TPCH database schema
10
Exercise 3 – TPCH Dataset
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Nations from multiple regions
11
Exercise 3 – TPCH Dataset
SELECT nationname
FROM
nation, region
WHERE
nation.regionid = region.regionid AND
( regionname = ’AMERICA’ OR
regionname = ’AFRICA’ OR
regionname = ’ASIA’ )
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Exclusive supplier
12
Exercise 3 – TPCH Dataset
SELECT COUNT(partid)
FROM part
WHERE partid IN
(SELECT partid
FROM supplypart sp, supplier su
WHERE sp.supplierid = su.supplierid AND
su.suppliername = ’Supplier#000000001’)
(SELECT partid
FROM supplypart sp, supplier su
WHERE sp.supplierid = su.supplierid AND
su.suppliername = ’Supplier#000000002’)
AND partid NOT IN
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First order
13
Exercise 3 – TPCH Dataset
SELECT
orderdate
FROM
orders o, customer c
WHERE
o.customerid = c.customerid AND
c.customername = ’Customer#000000001’
ORDER BY orderdate ASC
LIMIT 1;
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