I have several tables I"m trying to get data out of efficiently.
I have a drafted query as such:
SELECT products.id, products.name products.extended_description, products.catalogid, products.image1, products.image2, products.stock, products.price, manufacturer.manufacturer, products.weight
FROM products
JOIN manufacturer ON (products.manufacturer = manufacturer.id)
WHERE category.category_name = ?;
Obviously this is a broken query, but I'm not sure how to fix this. I need to somehow join category table to product_category table which is related to products table via the products.catalogid field.
My feeble attempt is as such:
SELECT products.id, products.name products.extended_description, products.catalogid, products.image1, products.image2, products.stock, products.price, manufacturer.manufacturer, products.weight
FROM products
JOIN manufacturer ON (products.manufacturer = manufacturer.id)
FROM category
JOIN product_category ON (category.id = (SELECT product_category.id FROM product_category WHERE product_category.catalogid /*I'm so lost...*/))
WHERE category.category_name = ?;
Basically I need to query the db for all the info in the SELECT clause where the category name is "NEW"... and I'm completely stumped (my SQL obviously needs some work!)
Something like this, just keeping joining and joining and....
SELECT
*
FROM
products as p
JOIN
manufacturer as m
ON
p.manufacturer = m.id
JOIN
product_category as pc
ON
pc.product = p.id
JOIN
category as c
ON
c.id=pc.category
WHERE
c.name = "NEW"
Since you've got a product_category table, it appears that your product may belong to multiple categories. In cases like that, you want to check if a category that you are looking for is among the categories assigned to your product.
One way of doing it is with an EXISTS condition:
SELECT p.id, p.name p.extended_description, p.catalogid, p.image1, p.image2, p.stock, p.price, m.manufacturer, p.weight
FROM products p
JOIN manufacturer m ON (p.manufacturer = m.id)
WHERE
EXISTS (
SELECT *
FROM product_category pc
JOIN category c ON c.id=pc.categoryId
WHERE pc.productId = p.id
AND c.category.category_name = ?
)
I assumed that the product_category many-to-many table has columns categoryId and productId which bring together the IDs of the product and a category to which that product belongs.
Related
In the equivalent of an Amazon product filter I have product classification ids coming from the front end as a table of ids. Each product can have many classifications. A normal join with my bridge table (ProductIds and ClassificationIds) returns products that have ANY of these ids. However I would like to return only those products that have ALL of the ids, thus meeting all of the customer's desires. An AND not an OR. How do I do this?
For example this is the typical join with test data for classification ids:
DECLARE #ClassifcationIds dbo.IdsTableNullable
INSERT INTO #ClassificationIds (Id)
VALUES (1),(2),(3)
SELECT DISTINCT
Id
Description
FROM dbo.Products as P
JOIN dbo.ProductClassification AS Pc ON P.Id = Pc.ProductId
JOIN #ClassifcationIds AS C ON C.Id = Pc.ClassificationId;
This returns products that have classification ids 1, 2, or 3. I only want products that have all three.
What is the equivalent of joining the bridge table on the first id, then joining the resulting table to the next id and so on until the resulting products have all 3 classification ids?
Use group by and having:
SELECT p.Id, p.Description
FROM dbo.Products P JOIN
dbo.ProductClassification Pc
ON P.Id = Pc.ProductId JOIN
#ClassifcationIds C
ON C.Id = Pc.ProductId
GROUP BY p.Id, p.Description
HAVING COUNT(*) = (SELECT COUNT(*) FROM #ClassifcationIds);
Having a bit of trouble with a basic SQL problem.
The question is that I have to find the salespersons first and last name, then their Social Insurance Number, the product description, the product price, and quantity sold where the total quantity sold is greater than 5.
I'll attach the database information below as a photo.
Product quantity sold greater than 5
SELECT ProductId
FROM ProductsSales
HAVING SUM(QuantitySold) > 5
Use that to get the rest:
SELECT s.FirstName, s.LastName, s.SIN, p.ProductDescription, ps.UnitSalesPrice, ps.QuantitySold
FROM ProductsSales ps
LEFT JOIN Products p on p.ProductID = ps.ProductID
LEFT JOIN Salesmen s on s.SalesmaneID = ps.SellerID
WHERE ps.ProductID IN
(
SELECT ProductId
FROM ProductsSales
GROUP BY ProductId
HAVING SUM(QuantitySold) > 5
)
SELECT a.FirstName, a.LastName, a.SIN, c.ProductDescription, b.UnitSalesPrice, b.QuantitySold
FROM Salesmen a
LEFT JOIN ProductsSales b
ON a.SalesmanId = b.SellerId
LEFT JOIN Products c
ON b.ProductId = c.ProductId
WHERE b.QuantitySold > 5
Select a.FirstName, a.LastName, a.SIN From Salesmen as a,
c.ProductDescriptio, c.Price, b.sum(QunatitySold)
inner join ProductSales as b on a.Salesmanid = b.sellerid
inner join Products as c on c.ProductId = b.ProductId
having b.sum(QunatitySold)> 5
group by a.FirstName, b.ProductDescription
Brad,
Welcome to SQL. Joining for me was a terrifying experience when I first started but its really easy. The general concept is this:
Pick a Join
If you want to see all records that would be common between the two table, you would use and JOIN. If you wanted to combine the two tables but still show all records you use LEFT JOIN
The basic syntax is
SELECT fieldnames FROM tablename alias
JOIN othertable alias ON firstalias.field = secondalias.field
--Example
SELECT animal, food, idtag from animals a
JOIN food f on a.animalid = f.animalid
This assumes you have a common field animalid in both the animals table and the food table. you should also ideally preface the field names with the alias to make it easier to understand like this: a.animal, f.food
And you keep going until you have joined all the tables you need.
Make sure you only request field names you want
Hope that helps
I have two tables Products and ProductProperties.
Products
name - string
description - text
etc etc
ProductProperties
product_id - integer
property_id - integer
There is also a table Properties which basically stores the list of property names and their attributes
How can I implement a SQL command that finds a product with the property_ids (A or B or C) AND (X or Y or Z)
I've got upto here:
SELECT DISTINCT "products".*
FROM "products"
INNER JOIN "product_properties" ON "product_properties"."product_id" = "products"."id" AND "product_properties"."deleted_at" IS NULL
WHERE "products"."deleted_at" IS NULL
AND (product_properties.property_id IN ('504, 506, 403'))
AND (product_properties.property_id IN ('520, 501, 502'))
But it doesn't really work since it's looking for a Product Property which has both values 504 and 520, which will never exist.
Would appreciate some help!
You need to define intermediate resultsets on a property group basis:
SELECT DISTINCT p.*
FROM products p
JOIN product_properties groupA ON groupA.product_id = p.id AND groupA.deleted_at IS NULL AND groupA.property_id IN ('504')
JOIN product_properties groupB ON groupB.product_id = p.id AND groupB.deleted_at IS NULL AND groupB.property_id IN ('520')
WHERE p.deleted_at IS NULL
You see, you detected the problem yourself very nicely: "But it doesn't really work since it's looking for a Product Property which has both values 504 and 520, which will never exist."
Indeed, recordsets are immutable within a query, all single criteria applied to them are applied all at once. You need to duplicate each table and apply individual criteria to them.
One method uses exists or in:
select p.*
from products p
where p.id in (select pp.product_id
from product_properties pp
where pp.propertyid in ('504', '520')
);
This saves you from having to use distinct in the outer query.
If, perchance, you really mean finding the products that have all the properties, then a join and group by work:
select p.*
from products p join
product_properties pp
on p.id = pp.product_id
where pp.propertyid in ('504', '520')
group by p.id -- yes, this is allowed in Postgres
having count(*) = 2;
Hi try this queries i just thinking about it so i didn't try any of them check i got the idea i want to do
SELECT DISTINCT "products".*
FROM products pr
WHERE id IN
(
SELECT product_id FROM ProductProperties WHERE property_id IN (504,520)
GROUP BY product_id
HAVING Count(*) = 2
) AND "products"."deleted_at" IS NULL
SELECT DISTINCT "products".*
FROM products pr, INNER JOIN (
SELECT product_id,count(*) as nbr FROM ProductProperties WHERE property_id IN (504,520)
GROUP BY product_id
) as temp ON temp.product_id = pr.id
WHERE "products"."deleted_at" IS NULL AND temp.nbr = 2
and also you can check this one as well ( you can use also the join in where clause instead of using INNER JOIN)
SELECT DISTINCT products.* FROM products as p
INNER JOIN product_properties as p1 ON p1.product_id = p.id
INNER JOIN product_properties as p2 ON p2.product_id = p.id
WHERE p.deleted_at IS NULL
AND p1.property_id = '504' AND p1.deleted_at IS NULL
AND p2.property_id = '520' AND p2.deleted_at IS NULL
I have three tables:
COLLECTION
PERSON
PERSON_COLLECTION
where PERSON_COLLECTION is a mapping table id|person_id|collection_id
I now want to select all entries in collection and order them by person.name.
Do I have to join the separate tables with the mapping table first and then do a join again on the results?
SELECT
c.*,
p.Name
FROM
Collection c
JOIN Person_Collection pc ON pc.collection_id = c.id
JOIN Person p ON p.id = pc.person_id
ORDER BY p.Name
Not sure without the table schema but, my take is:
SELECT
c.*,
p.*
FROM
Person_Collection pc
LEFT JOIN Collection c
ON pc.collection_id = c.id
LEFT JOIN Person p
ON pc.person_id = p.id
ORDER BY p.name
The order you join won't break it but depending on which sql product you're using may effect performance.
You need to decide if you want ALL records from both/either table or only records which have a matching mapping entry, this will change the type of join you need to use.
SQL Server 2005.
I've a link table of Products and Attributes associated with them. I'm doing a search along the lines of:
select distinct ProductId from productattributelink where
attributeid in (25,5,44,46)
But I want to make sure that each productid is also associated with an attributeId of 10.
So in longhand the query would be: Show me all the product Ids that have the following attributeids (25,5,44,46) but also have attributeid of 10.
I've a feeling this is really obvious but is eluding me.
select distinct p.ProductId from product p
inner join productattributelink pa1 on pa1.ProductId = p.ProductId
inner join productattributelink pa2 on pa2.ProductId = p.ProductId
where pa1.attributeid IN(25,5,44,46) and pa2.attributeid = 10
You should join the table to itself:
select distinct ProductId from productattributelink p1
JOIN productattributelink p2 ON p1.ProductId = p2.ProductId
where p1.attributeid in (25,5,44,46) AND p2.attributeid = 10