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
Related
I have these 3 tables:
Bill:
idBill
Products:
idProduct
price
BillProducts (that connects the tables above):
idBill
idProduct
quantity
Now let's say I wish to get the total price of a certain bill identified by its ID
I would need to multiply the columns of Products.Price by BillProducts.quantity, get its result and sum all the others products in that idBill
Can you guys help me writing that query?
SELECT SUM(QUANTxPRICE) AS SUMED, IDBILL FROM (
SELECT (A.QUANTITY * B.PRICE) AS QUANTxPRICE,a.IDBILL
FROM BILLPRODUCTS AS A
JOIN PRODUCTS AS B ON
A.IDPRODUCT = B.IDPRODUCT
JOIN BILL AS C
ON A.IDBILL = C.IDBILL
) AS X
GROUP BY IDBILL
You would do:
select sum(p.price * bp.product)
from billproducts bp join
products p
on bp.idproduct = p.idproduct
where idbill = <idbill>;
You can get this for all bills using group by:
select idbill, sum(p.price * bp.product)
from billproducts bp join
products p
on bp.idproduct = p.idproduct
group by idbill;
Notes:
You do not need to join the bills table. All the information you need is in the other two tables.
You do not need a subquery.
When you define table aliases, they should be abbreviations for the table names, so the query is easier to follow.
I have 3 datasets: company, post, postedited,
I want to count the numbers of companies' post and postedited. some companies post but did not edited.
here is my query :
SELECT company.name, company.id, count(*),
( select count(*)
from post, postedited
where post.id=postedited.post_id)
from company, post as p
where company.id=p.company_id
group by company_id
the outcome of post is right, but the column of postedited is the same. what's wrong with my query?
Your subquery is completely unrelated to the main query. It selects post and postedited and counts. You are showing this result for every row of the main query.
You want the subquery relate to the main query's post. So remove the post table from the subquery's from clause:
(select count(*) from postedited where postedited.post_id = p.id)
Now this subquery selects a count for the post_id of the main query's records. At last you must get the sum of the counts:
select
c.name, c.id, count(*) as posts,
sum(select count(*) from postedited pe where pe.post_id = p.id) as edits
from company c
join post p on p.company_id = c.id
group by c.id;
You can achieve the same thus:
select
c.name, c.id, count(distinct p.id) as posts, count(pe.post_id) as edits
from company c
join post p on p.company_id = c.id
left join postedited pe on pe.post_id = p.id
group by c.id;
SELECT c.name AS companyName
, c.id AS companyID
, COUNT(DISTINCT p.id) AS postCount
, COUNT(DISTINCT pe.post_id) AS postEditCount
FROM company c
LEFT OUTER JOIN post p ON p.Company_ID = c.ID
LEFT OUTER JOIN postEdited pe ON pe.Company_ID = c.ID
GROUP BY c.id, c.name
That will give you a list of all companies in your company table with a count of each of their posts and edited posts. If you need to further query against that dataset, you can. Or you can add a WHERE clause to the above query to filter it.
And I agree, please don't use comma syntax. It's very easy to produce unintended results, and it doesn't give a good representation of what you're actually querying against. Plus, it's no longer standard and being deprecated in many flavors of SQL. Good JOIN syntax will make your life much easier.
I am using SQL Server to query these three tables that look like (there are some extra columns but not that relevant):
Customers -> Id, Name
Addresses -> Id, Street, StreetNo, CustomerId
Sales -> AddressId, Week, Total
And I would like to get the total sales per week and customer (showing at the same time the address details). I have come up with this query
SELECT a.Name, b.Street, b.StreetNo, c.Week, SUM (c.Total) as Total
FROM Customers a
INNER JOIN Addresses b ON a.Id = b.CustomerId
INNER JOIN Sales c ON b.Id = c.AddressId
GROUP BY a.Name, c.Week, b.Street, b.StreetNo
and even if my SQL skill are close to none it looks like it's doing its job. But now I would like to be able to show 0 whenever the one customer don't have sales for a particular week (weeks are just integers). And I wonder if somehow I should get distinct values of the weeks in the Sales table, and then loop through them (not sure how)
Any help?
Thanks
Use CROSS JOIN to generate the rows for all customers and weeks. Then use LEFT JOIN to bring in the data that is available:
SELECT c.Name, a.Street, a.StreetNo, w.Week,
COALESCE(SUM(s.Total), 0) as Total
FROM Customers c CROSS JOIN
(SELECT DISTINCT s.Week FROM sales s) w LEFT JOIN
Addresses a
ON c.CustomerId = a.CustomerId LEFT JOIN
Sales s
ON s.week = w.week AND s.AddressId = a.AddressId
GROUP BY c.Name, a.Street, a.StreetNo, w.Week;
Using table aliases is good, but the aliases should be abbreviations for the table names. So, a for Addresses not Customers.
You should generate a week numbers, rather than using DISTINCT. This is better in terms of performance and reliability. Then use a LEFT JOIN on the Sales table instead of an INNER JOIN:
SELECT a.Name
,b.Street
,b.StreetNo
,weeks.[Week]
,COALESCE(SUM(c.Total),0) as Total
FROM Customers a
INNER JOIN Addresses b ON a.Id = b.CustomerId
CROSS JOIN (
-- Generate a sequence of 52 integers (13 x 4)
SELECT ROW_NUMBER() OVER (ORDER BY a.x) AS [Week]
FROM (VALUES(1),(1),(1),(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) a(x)
CROSS JOIN (SELECT x FROM (VALUES(1),(1),(1),(1)) b(x)) b
) weeks
LEFT JOIN Sales c ON b.Id = c.AddressId AND c.[Week] = weeek.[Week]
GROUP BY a.Name
,b.Street
,b.StreetNo
,weeks.[Week]
Please try the following...
SELECT Name,
Street,
StreetNo,
Week,
SUM( CASE
WHEN Total IS NULL THEN
0
ELSE
Total
END ) AS Total
FROM Customers a
JOIN Addresses b ON a.Id = b.CustomerId
RIGHT JOIN Sales c ON b.Id = c.AddressId
GROUP BY a.Name,
c.Week,
b.Street,
b.StreetNo;
I have modified your statement in three places. The first is I changed your join to Sales to a RIGHT JOIN. This will join as it would with an INNER JOIN, but it will also keep the records from the table on the right side of the JOIN that do not have a matching record or group of records on the left, placing NULL values in the resulting dataset's fields that would have come from the left of the JOIN. A LEFT JOIN works in the same way, but with any extra records in the table on the left being retained.
I have removed the word INNER from your surviving INNER JOIN. Where JOIN is not preceded by a join type, an INNER JOIN is performed. Both JOIN and INNER JOIN are considered correct, but the prevailing protocol seems to be to leave the INNER out, where the RDBMS allows it to be left out (which SQL-Server does). Which you go with is still entirely up to you - I have left it out here for illustrative purposes.
The third change is that I have added a CASE statement that tests to see if the Total field contains a NULL value, which it will if there were no sales for that Customer for that Week. If it does then SUM() would return a NULL, so the CASE statement returns a 0 instead. If Total does not contain a NULL value, then the SUM() of all values of Total for that grouping is performed.
Please note that I am assuming that Total will not have any NULL values other than from the RIGHT JOIN. Please advise me if this assumption is incorrect.
Please also note that I have assumed that either there will be no missing Weeks for a Customer in the Sales table or that you are not interested in listing them if there are. Again, please advise me if this assumption is incorrect.
If you have any questions or comments, then please feel free to post a Comment accordingly.
I have the following tables:
**products** which has these fields: id,product,price,added_date
**products_to_categories** which has these fields: id,product_id,category_id
**adverts_to_categories** -> id,advert_id,category_id
**adverts** which has these fields: id,advert_name,added_date,location
I can not execute sql that will return to me all products that are from category 14 and that are owned by advert located in London. So I have 4 tables and 2 conditions - to be from category 14 and the owner of the product to be from London. I tried many variants to execute sql but none of the results were correct.. Do I need to use Join and which Join - left, right, full? How the correct sql will look like? thank you in advance for your help and sorry for boring you :)
This is what I have tried so far:
SELECT p.id, product, price, category_id,
p.added_date, adverts.location, adverts.id
FROM products p,
products_to_categories ptc,
adverts,
adverts_to_categories ac
WHERE ptc.category_id = "14"
AND ptc.product_id=p.id
AND ac.advert_id=adverts.id
AND adverts.location= "London"
pretty basic logic
Select * from Products P
INNER JOIN Products_To_Categories PTC ON P.ID = PTC.Product_ID
INNER JOIN Adverts_to_Categories ATC ON ATC.Category_Id = PTC.Category_ID
INNER JOIN Adverts AD on AD.ID = ATC.Advert_ID
WHERE PTC.Category_ID = 14 and AD.Location = 'LONDON'
you would only need a LEFT or right join IF you wanted records from a table which didn't exist in other tables.
so for example, if you wanted all products even if a records even those without a category, then you would use a LEFT Join instead of inner.
The following statement should return all columns from the product table in category with id 14 and all adverts located in London:
select p.* from products p
inner join products_to_categories pc on p.id = pc.product_id
inner join adverts_to_categories ac on pc.category_id = ac.category_id
inner join adverts a on a.id = ac.advert_id
where pc.category_id = 14
and ac.location = 'London';
You should remember to add an index to the column location if you are doing these string-based queries very often.
I have four tables: Customer, CustomerCategory, Limit, and LimitCategory. A customer can be in multiple categories and a limit can also have multiple categories. I need to write a query that will return the customer name and limit amount where ALL the customers categories match ALL the limit categories.
I'm guessing it would be similar to the answer here, but I can't seem to get it right. Thanks!
Edit - Here's what the tables look like:
tblCustomer
customerId
name
tblCustomerCategory
customerId
categoryId
tblLimit
limitId
limit
tblLimitCategory
limitId
categoryId
I THINK you're looking for:
SELECT *
FROM CustomerCategory
LEFT OUTER JOIN Customer
ON CustomerCategory.CustomerId = Customer.Id
INNER JOIN LimitCategory
ON CustomerCategory.CategoryId = LimitCategory.CategoryId
LEFT OUTER JOIN Limit
ON Limit.Id = LimitCategory.LimitId
Updated!
Thanks to Felix for pointing out a flaw in my existing solution (3 years after I originally posted it, hehe). After looking at it again, I think this might be correct. Here I'm getting (1) the customers and limits with matching categories, plus the number of matching categories, (2) the number of categories per customer, (3) the number of categories per limit, (4) I then ensure the number of categories for customer and limits is the same as the number of the matches between the customers and limits:
UNTESTED!
select
matches.name,
matches.limit
from (
select
c.name,
c.customerId,
l.limit,
l.limitId,
count(*) over(partition by cc.customerId, lc.limitId) as matchCount
from tblCustomer c
join tblCustomerCategory cc on c.customerId = cc.customerId
join tblLimitCategory lc on cc.categoryId = lc.categoryId
join tblLimit l on lc.limitId = l.limitId
) as matches
join (
select
cc.customerId,
count(*) as categoryCount
from tblCustomerCategory cc
group by cc.customerId
) as customerCategories
on matches.customerId = customerCategories.customerId
join (
select
lc.limitId,
count(*) as categoryCount
from tblLimitCategory lc
group by lc.limitId
) as limitCategories
on matches.limitId = limitCategories.limitId
where matches.matchCount = customerCategories.categoryCount
and matches.matchCount = limitCategories.categoryCount
I don't know if this will work or not, just a thought i had and i can't test it, I'm sures theres a nicer way! don't be too harsh :)
SELECT
c.customerId
, l.limitId
FROM
tblCustomer c
CROSS JOIN
tblLimit l
WHERE NOT EXISTS
(
SELECT
lc.limitId
FROM
tblLimitCategory lc
WHERE
lc.limitId = l.id
EXCEPT
SELECT
cc.categoryId
FROM
tblCustomerCategory cc
WHERE
cc.customerId = l.id
)