what am trying to do is displaying only the fk_students who got marks in biology and chemistry and computer like 5 3 3 respectively but not 2 which considered as a failure here the result am getting also the students who got 2 marks in the subjects.
*
select school_name,fk_students, count(marks),sum(marks) as total from students inner join remarks on fk_students = student_id
inner join subjects on subject_id = fk_subjects
inner join school on school_id = fk_school_idd
where marks = 3 or marks = 4 or marks = 5
group by fk_students,school_name
except
select school_name,fk_students, count(marks),sum(marks) as total from students inner join remarks on fk_students = student_id
inner join subjects on subject_id = fk_subjects
inner join school on school_id = fk_school_idd
where marks =2
group by fk_students,school_name
order by fk_students
the column fk_students where it contains 9 and 10 and 11 shouldn't be shown because they've got 2 mark in of their subjects which is considered failure
result
I solved this problem by using "where in"
full solution is shown below
select school_name,st_name,sum(marks) as total from students inner
join remarks on fk_students = student_id
inner join subjects on subject_id = fk_subjects
inner join school on school_id = fk_school_idd
group by fk_students,school_name,st_name
having sum(marks)=15
except
select school_name,st_name,sum(marks) as total from students inner
join remarks on fk_students = student_id
inner join subjects on subject_id = fk_subjects
inner join school on school_id = fk_school_idd
where fk_students = any(select fk_students from remarks
where marks in (2))
group by fk_students,school_name,st_name
having sum(marks)=15
order by school_name
Related
I want to group the records by relation.
products table:
id
price
1
100
2
200
3
300
4
400
product_properties table:
id
productId
propertyId
1
1
2
2
1
3
3
2
2
4
2
3
5
3
4
6
4
4
The query should select lowest price group by product_properties. I mean, If products have same properties in product_properties, query should return product that has lowest price.
So, For these tables query should return products that have ids 1,3.
I use TypeORM, I tried join the relation and distinct on relation alias name but its not worked.
How can I achieve this?
I wrote two variants query for you:
-- variant 1
select distinct t1.product_id from (
select
pr.price, pp.product_id, pp.property_id, min(pr.price) OVER(PARTITION BY pp.property_id) as min_price
from
test.product_properties pp
inner join
test.products pr on pp.product_id = pr.id
) t1
where
t1.price = t1.min_price;
-- variant 2
select distinct t1.product_id from test.product_properties t1
inner join test.products t2 on t1.product_id = t2.id
inner join (
select
pp.property_id, min(pr.price) as min_price
from
test.product_properties pp
inner join
test.products pr on pp.product_id = pr.id
group by pp.property_id
) t3 on t3.property_id = t1.property_id and t3.min_price = t2.price;
I have the following tables:
dealer
id (PK)
car
- id (PK)
- dealer_id (FK)
notes
- car_id (FK)
- dealer_id (FK)
- user_id (FK)
- is_active Bool
I want to be able to select all dealers that I have active notes for. Current model does not store dealer_id on notes and car_id on notes at once. It's an either or.
I can do the queries separately:
select *
from dealer
inner join notes n on dealer.id = n.dealer_id and n.user_id=${userId} and n.is_active=true
and:
select *
from dealer
inner join car c on dealer.id = c.dealer_id
inner join notes n on c.id = n.car_id and n.user_id=${userId} and n.is_active=true
I tried to simply combine the two inner joins in the queries but then the:
inner join car c on dealer.id = c.dealer_id
would sift out what the first query would give me and so I would not get all the dealers I should be getting.
How can I write one query that gives me all the dealers I have active notes for?
I would like not to get duplicate dealers in the result.
You're almost there. What you want is called UNION:
SELECT n.*
FROM
notes AS n
INNER JOIN dealer AS d ON d.id = n.dealer_id
UNION
SELECT n.*
FROM
notes AS n
INNER JOIN car AS c ON c.id = n.car_id
INNER JOIN dealer AS d ON d.id = c.dealer_id
I have a many to many relation with three columns, (owner_id,property_id,ownership_perc) and for this table applies (many owners have many properties).
So I would like to find all the owner_id who has many properties (property_id) and connect them with other three tables (Table 1,3,4) in order to get further information for the requested result.
All the tables that I'm using are
Table 1: owner (id_owner,name)
Table 2: owner_property (owner_id,property_id,ownership_perc)
Table 3: property(id_property,building_id)
Table 4: building(id_building,address,region)
So, when I'm trying it like this, the query runs but it returns empty.
SELECT address,region,name
FROM owner_property
JOIN property ON owner_property.property_id = property.id_property
JOIN owner ON owner.id_owner = owner_property.owner_id
JOIN building ON property.building_id=building.id_building
GROUP BY owner_id,address,region,name
HAVING count(owner_id) > 1
ORDER BY owner_id;
Only when I'm trying the code below, it returns the owner_id who has many properties (see image below) but without joining it with the other three tables:
SELECT a.*
FROM owner_property a
JOIN (SELECT owner_id, COUNT(owner_id)
FROM owner_property
GROUP BY owner_id
HAVING COUNT(owner_id)>1) b
ON a.owner_id = b.owner_id
ORDER BY a.owner_id,property_id ASC;
So, is there any suggestion on what I'm doing wrong when I'm joining the tables? Thank you!
This query:
SELECT owner_id
FROM owner_property
GROUP BY owner_id
HAVING COUNT(property_id) > 1
returns all the owner_ids with more than 1 property_ids.
If there is a case of duplicates in the combination of owner_id and property_id then instead of COUNT(property_id) use COUNT(DISTINCT property_id) in the HAVING clause.
So join it to the other tables:
SELECT b.address, b.region, o.name
FROM (
SELECT owner_id
FROM owner_property
GROUP BY owner_id
HAVING COUNT(property_id) > 1
) t
INNER JOIN owner_property op ON op.owner_id = t.owner_id
INNER JOIN property p ON op.property_id = p.id_property
INNER JOIN owner o ON o.id_owner = op.owner_id
INNER JOIN building b ON p.building_id = b.id_building
ORDER BY op.owner_id, op.property_id ASC;
Always qualify the column names with the table name/alias.
You can try to use a correlated subquery that counts the ownerships with EXISTS in the WHERE clause.
SELECT b1.address,
b1.region,
o1.name
FROM owner_property op1
INNER JOIN owner o1
ON o1.id_owner = op1.owner_id
INNER JOIN property p1
ON p1.id_property = op1.property_id
INNER JOIN building b1
ON b1.id_building = p1.building_id
WHERE EXISTS (SELECT ''
FROM owner_property op2
WHERE op2.owner_id = op1.owner_id
HAVING count(*) > 1);
I have a products table and corresponding ratings table which contains a foreign key product_id, grade(int) and type which is an enum accepting values robustness and price_quality_ratio
The grades accept values from 1 to 10. So for example, how would the query look like, if I wanted to filter the products where minimum grade for robustness would be 7 and minimum grade for price_quality_ratio would be 8?
You can join twice, once per rating. The inner joins eliminate the products that fail any rating criteria,
select p.*
from products p
inner join rating r1
on r1.product_id = p.product_id
and r1.type = 'robustness'
and r1.rating >= 7
inner join rating r2
on r2.product_id = p.product_id
and r2.type = 'price_quality_ratio'
and r2.rating >= 8
Another option is to use do conditional aggregation. This requires only one join, then a group by; the rating criteria are checked in the having clause.
select p.product_id, p.product_name
from products p
inner join rating r
on r.product_id = p.product_id
and r.type in ('robustness', 'price_quality_ratio')
group by p.product_id, p.product_name
having
min(case when r.type = 'robustness' then r.rating end) >= 7
and min(case when r.type = 'price_quality_ratio then r.rating end) >= 8
The JOIN proposed by #GMB would've been my first suggestion as well. If that gets too complicated with having to maintain too many rX.ratings, you can also use a nested query:
SELECT *
FROM (
SELECT p.*, r1.rating as robustness, r2.rating as price_quality_ratio
FROM products p
JOIN rating r1 ON (r1.product_id = p.product_id AND r1.type = 'robustness')
JOIN rating r2 ON (r2.product_id = p.product_id AND r2.type = 'price_quality_ratio')
) AS tmp
WHERE robustness >= 7
AND price_quality_ratio >= 8
-- ORDER BY (price_quality_ratio DESC, robustness DESC) -- etc
I have 2 tables
students:
id | name | age
1 abc 20
2 xyz 21
scores:
id | studentid | marks
1 1 20
2 2 22
3 2 20
4 1 22
5 1 20
where studentid is foreign key to students table
When a do
select studentid
from scores
where marks=20;
I get the following result
1, 2, 1
But if want the name of the student name and when I do a join using
select t1.name
from students t1
inner join scores t2 on t1.id = t2.studentid
where t2.marks=20;
I get xyz,abc,abc Though the ouput is correct is there any way I can maintain the order in which scores are listed in the scores table? I should get abc,xyz,abc as output. I tried using subquery as well
SELECT name
FROM students
WHERE ID IN ( select studentid from scores where marks=20) ;
but that also did not give me correct order. How can this be achieved using CTEs (common table expressions)? I tried the follownig cte but it did not work
with cte as(
select t2.id, t1.name
from students t1
inner join scores t2 on t1.id = t2.studentid
where t2.marks=20)
select name from cte order by id
You can order by a column not present in select list:
select t1.name
from students t1
inner join scores t2 on t1.id = t2.student_id
where t2.marks=20
order by t2.id;
name
------
abc
xyz
abc
(3 rows)