SQL Division Operator and implementation in Mysql
In a database i have some cars that are rented by customers. I want to find the cars that were rented by All Customers, and display their PlateNr. In other words i want to make SQL Division in MySql.
My Database is like this:
Customer
ID,Name
1 , John
2 , Scott
Car
PlateNr,Colour
1111 , red
2222 , black
Rents
ID , PlateNr , Date
1, 1111, 2010-01-01
1, 1111, 2010-02-01
2, 1111, 2010-03-02
2, 2222, 2010-01-02
Following some instructions i have the following query, but it doesn't work to find the car that was rented by all customers (correct result should be Platenr=1111). What is wrong with the query?
SELECT PlateNr
FROM rents as R1
WHERE NOT EXISTS
(SELECT car.PlateNr
FROM car
WHERE NOT EXISTS
(SELECT rents.PlateNr
FROM rents
WHERE rents.PlateNr=R1.PlateNr));
mysql
add a comment |
In a database i have some cars that are rented by customers. I want to find the cars that were rented by All Customers, and display their PlateNr. In other words i want to make SQL Division in MySql.
My Database is like this:
Customer
ID,Name
1 , John
2 , Scott
Car
PlateNr,Colour
1111 , red
2222 , black
Rents
ID , PlateNr , Date
1, 1111, 2010-01-01
1, 1111, 2010-02-01
2, 1111, 2010-03-02
2, 2222, 2010-01-02
Following some instructions i have the following query, but it doesn't work to find the car that was rented by all customers (correct result should be Platenr=1111). What is wrong with the query?
SELECT PlateNr
FROM rents as R1
WHERE NOT EXISTS
(SELECT car.PlateNr
FROM car
WHERE NOT EXISTS
(SELECT rents.PlateNr
FROM rents
WHERE rents.PlateNr=R1.PlateNr));
mysql
add a comment |
In a database i have some cars that are rented by customers. I want to find the cars that were rented by All Customers, and display their PlateNr. In other words i want to make SQL Division in MySql.
My Database is like this:
Customer
ID,Name
1 , John
2 , Scott
Car
PlateNr,Colour
1111 , red
2222 , black
Rents
ID , PlateNr , Date
1, 1111, 2010-01-01
1, 1111, 2010-02-01
2, 1111, 2010-03-02
2, 2222, 2010-01-02
Following some instructions i have the following query, but it doesn't work to find the car that was rented by all customers (correct result should be Platenr=1111). What is wrong with the query?
SELECT PlateNr
FROM rents as R1
WHERE NOT EXISTS
(SELECT car.PlateNr
FROM car
WHERE NOT EXISTS
(SELECT rents.PlateNr
FROM rents
WHERE rents.PlateNr=R1.PlateNr));
mysql
In a database i have some cars that are rented by customers. I want to find the cars that were rented by All Customers, and display their PlateNr. In other words i want to make SQL Division in MySql.
My Database is like this:
Customer
ID,Name
1 , John
2 , Scott
Car
PlateNr,Colour
1111 , red
2222 , black
Rents
ID , PlateNr , Date
1, 1111, 2010-01-01
1, 1111, 2010-02-01
2, 1111, 2010-03-02
2, 2222, 2010-01-02
Following some instructions i have the following query, but it doesn't work to find the car that was rented by all customers (correct result should be Platenr=1111). What is wrong with the query?
SELECT PlateNr
FROM rents as R1
WHERE NOT EXISTS
(SELECT car.PlateNr
FROM car
WHERE NOT EXISTS
(SELECT rents.PlateNr
FROM rents
WHERE rents.PlateNr=R1.PlateNr));
mysql
mysql
asked Nov 14 '18 at 7:17
ritgeoritgeo
416
416
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
I would write this query as:
SELECT PlateNr
FROM Rents
GROUP BY PlateNr
HAVING COUNT(DISTINCT ID) = (SELECT COUNT(*) FROM Customer);
In plain English, this says to find all plates whose distinct count of renting customers matches the total number of customers. I assume here that ID
is a unique column in the Customers
table.
add a comment |
With this query you can see which customer rented which car and how many times, ıf you can ask something else you can add a comment
Select Customer.Name,Car.PlateNr,count(*) as Count
from Customer inner join Rents On Rents.ID=Customer.ID
inner join Car On Car.PlateNr=Rents.PlateNr
group by Customer.Name,Car.PlateNr
having count(*)>1
Thanks Yusuf. It doesnt work, bu if i replace Car,PlateNr with Car.PlateNr it works as you describe.
– ritgeo
Nov 14 '18 at 7:52
Yes I corrected it,
– yusuf hayırsever
Nov 14 '18 at 7:53
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
I would write this query as:
SELECT PlateNr
FROM Rents
GROUP BY PlateNr
HAVING COUNT(DISTINCT ID) = (SELECT COUNT(*) FROM Customer);
In plain English, this says to find all plates whose distinct count of renting customers matches the total number of customers. I assume here that ID
is a unique column in the Customers
table.
add a comment |
I would write this query as:
SELECT PlateNr
FROM Rents
GROUP BY PlateNr
HAVING COUNT(DISTINCT ID) = (SELECT COUNT(*) FROM Customer);
In plain English, this says to find all plates whose distinct count of renting customers matches the total number of customers. I assume here that ID
is a unique column in the Customers
table.
add a comment |
I would write this query as:
SELECT PlateNr
FROM Rents
GROUP BY PlateNr
HAVING COUNT(DISTINCT ID) = (SELECT COUNT(*) FROM Customer);
In plain English, this says to find all plates whose distinct count of renting customers matches the total number of customers. I assume here that ID
is a unique column in the Customers
table.
I would write this query as:
SELECT PlateNr
FROM Rents
GROUP BY PlateNr
HAVING COUNT(DISTINCT ID) = (SELECT COUNT(*) FROM Customer);
In plain English, this says to find all plates whose distinct count of renting customers matches the total number of customers. I assume here that ID
is a unique column in the Customers
table.
answered Nov 14 '18 at 7:26
Tim BiegeleisenTim Biegeleisen
223k1391143
223k1391143
add a comment |
add a comment |
With this query you can see which customer rented which car and how many times, ıf you can ask something else you can add a comment
Select Customer.Name,Car.PlateNr,count(*) as Count
from Customer inner join Rents On Rents.ID=Customer.ID
inner join Car On Car.PlateNr=Rents.PlateNr
group by Customer.Name,Car.PlateNr
having count(*)>1
Thanks Yusuf. It doesnt work, bu if i replace Car,PlateNr with Car.PlateNr it works as you describe.
– ritgeo
Nov 14 '18 at 7:52
Yes I corrected it,
– yusuf hayırsever
Nov 14 '18 at 7:53
add a comment |
With this query you can see which customer rented which car and how many times, ıf you can ask something else you can add a comment
Select Customer.Name,Car.PlateNr,count(*) as Count
from Customer inner join Rents On Rents.ID=Customer.ID
inner join Car On Car.PlateNr=Rents.PlateNr
group by Customer.Name,Car.PlateNr
having count(*)>1
Thanks Yusuf. It doesnt work, bu if i replace Car,PlateNr with Car.PlateNr it works as you describe.
– ritgeo
Nov 14 '18 at 7:52
Yes I corrected it,
– yusuf hayırsever
Nov 14 '18 at 7:53
add a comment |
With this query you can see which customer rented which car and how many times, ıf you can ask something else you can add a comment
Select Customer.Name,Car.PlateNr,count(*) as Count
from Customer inner join Rents On Rents.ID=Customer.ID
inner join Car On Car.PlateNr=Rents.PlateNr
group by Customer.Name,Car.PlateNr
having count(*)>1
With this query you can see which customer rented which car and how many times, ıf you can ask something else you can add a comment
Select Customer.Name,Car.PlateNr,count(*) as Count
from Customer inner join Rents On Rents.ID=Customer.ID
inner join Car On Car.PlateNr=Rents.PlateNr
group by Customer.Name,Car.PlateNr
having count(*)>1
edited Nov 14 '18 at 7:53
answered Nov 14 '18 at 7:38
yusuf hayırseveryusuf hayırsever
1877
1877
Thanks Yusuf. It doesnt work, bu if i replace Car,PlateNr with Car.PlateNr it works as you describe.
– ritgeo
Nov 14 '18 at 7:52
Yes I corrected it,
– yusuf hayırsever
Nov 14 '18 at 7:53
add a comment |
Thanks Yusuf. It doesnt work, bu if i replace Car,PlateNr with Car.PlateNr it works as you describe.
– ritgeo
Nov 14 '18 at 7:52
Yes I corrected it,
– yusuf hayırsever
Nov 14 '18 at 7:53
Thanks Yusuf. It doesnt work, bu if i replace Car,PlateNr with Car.PlateNr it works as you describe.
– ritgeo
Nov 14 '18 at 7:52
Thanks Yusuf. It doesnt work, bu if i replace Car,PlateNr with Car.PlateNr it works as you describe.
– ritgeo
Nov 14 '18 at 7:52
Yes I corrected it,
– yusuf hayırsever
Nov 14 '18 at 7:53
Yes I corrected it,
– yusuf hayırsever
Nov 14 '18 at 7:53
add a comment |
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