I'm new to databases and I'm having a hard time figuring this out. Any assistance would be greatly appreciated
Deliveries Table
-- ID (PK)
-- DriverID (FK to Drivers Table)
Drivers Table
-- ID (PK)
-- LocationID (FK to Locations Table)
Locations Table
-- ID (PK)
-- RestaurantID (FK to Restaurants Table)
Restaurant Table
--ID (PK)
A Restaurant can have multiple locations (1 to many). A location can have multiple drivers (1 to many). a Driver can have multiple deliveries (1 to many). This design is supposed to break things out in 3rd normal form. So if I want to go to the deliveries table and get all of the deliveries associated with a particular restaurant, how would I query or do a join for that? Would I have to add a second foreign key to Deliveries that directly references the Restaurant table? I think after I see the query I can figure out what is going on. Thx
You can use left or right outer join to make a combined table and then you can easily query it, or else you can use a query with multiple sub-queries inside it to attain the required result without using join. Here is an example on how to use sub-query for your use-case.
SELECT ID FROM Deliveries De
WHERE De."DriverID" IN (SELECT ID FROM Drivers Dr
WHERE Dr. "LocationID" IN (SELECT ID FROM Locations L
WHERE L. "RestaurantID" IN (SELECT ID FROM Restaurant)))
I hope this solves your issue without using join statement.
You can use inner join or union depending on what you want to achieve. Example:
SELECT a."articleId" AS id, a.title, a."articleImage" AS "articleImage/url", c.category AS "category/public_id", a."createdOn", concat("firstName", ' ', "lastName") AS author
FROM articles a
INNER JOIN users u ON a."userId" = u."userId"
INNER JOIN categories c ON a."categoryId" = c."categoryId"
UNION
SELECT g."gifId" AS id, g.title, g."imageUrl" AS "articleImage/url", g.public_id AS "category/public_id", g."createdOn", concat("firstName", ' ', "lastName") AS author
FROM gifs g
INNER JOIN users u ON g."userId" = u."userId"
ORDER BY "createdOn" DESC
You can say how you want to get the results for more detailed query.
If I understand what you want to do then it maybe like this,
1st you have to join all those table to get corresponding result you want,
the join condition will be
select <your desire column name>
from Restaurant A,Locations B,Drivers C,Deliveries D
where A.ID = B.RestaurantID
and B.ID = C.LocationID
and C.ID = D.DriverID
Hope this is helpful, fell free to say anything.
Related
I am getting my face kicked in....
I have a total of 4 tables
1. Business (BusinessID, CustomerID, BusName, Territory)
2. Customer (CustomerID, Name)
3. Sales (BusinessID, CustomerID, Territory, Jan, Feb, Mar, Apr, May, Jun)
4. Performance (this is the table I want the info in)
I've already created the table to have the following columns, BusinessID, CustomerID, BusName, Name, Territory, Jan,Feb,Mar,Apr,May,Jun
Every time I try to insert its not properly joining and I am getting a bunch of errors "multi-part identifier could not be bound"
insert into Performance (BusinessID, CustomerID, BusName, Name, Territory, January2018, February2018, March2018, April2018, May2018, June2018)
select Business.BusinessID, Customer.CustomerID, Business.BusName, Customer.Name, Sales.Territory, Sales.January2018, Sales.February2018, Sales.March2018, Sales.April2018, Sales.May2018, Sales.June2018
from Business A
inner join Customer B ON a.CustomerID = b.CustomerID
inner join Sales C ON b.CustomerID = c.CustomerID;
Due to this error I had to do 3 seperate insert into and that caused a bunch of nulls....
face palm is happening and could use some advice.
Image: enter image description here
Thanks,
VeryNew2SQL
You have used table ALIASES, so you have to use those aliases in you SELECT
A for Business, B for Customer and C for Sales.
Read about ALIASES here.
select A.BusinessID, B.CustomerID, A.BusName, B.Name, C.Territory, C.January2018, C.February2018, C.March2018, C.April2018, C.May2018, C.June2018
from Business A
inner join Customer B ON a.CustomerID = b.CustomerID
inner join Sales C ON b.CustomerID = c.CustomerID;
When you create a table alias in your FROM and JOIN clauses, you need to refer to the aliases in your SELECT statement and not the actual table names.
Alternatively, leave your SELECT statement as it is, and adjust your table names to remove the alias. You'll then need the join conditions to refer to your actual table names, rather than the alias. So for example;
select Business.BusinessID, Customer.CustomerID, Business.BusName, Customer.Name, Sales.Territory, Sales.January2018, Sales.February2018, Sales.March2018, Sales.April2018, Sales.May2018, Sales.June2018
from Business
inner join Customer ON Business.CustomerID = Customer.CustomerID
inner join Sales ON Customer.CustomerID = Sales.CustomerID;
Even just try running the SELECT statement above first to make sure you get the query correct before trying it in your insert.
I am trying to build hierarchies by nesting queries on the same table in MS SQL Server 2014.
To give an example of what I am trying to achieve:
I have a table 'employees' whith the following columns:
[ID],[First Name],[Last Name],[ReportsTo]
{1},{John},{Doe},{2}
{2},{Mary},{Miller},{NULL}
I am trying to build a statement, where I join the employees table with itself and where I build a hierarchy with the boss on top.
Expected Result:
[Employee],[Boss]
{Miller,Mary},{NULL}
{Doe, John},{Miller,Mary}
I apologize, if this is a stupid question, but I fail to create a working nested query.
Could you please help me with that?
Thank you very much in advance
Based on the intended results, it looks like what you essentially want is a list of employees. So let's start with that:
SELECT LastName, FirstName, ReportsTo FROM Employees
This gives you the list, so you now have the objects you're looking for. But you need to fill out more data. You want to follow ReportsTo and show data from the record to which that points as well. This would be done exactly as it would if the foreign key pointed to a different table. (The only difference from being the same table is that you must use table aliases in the query, since you're including the same table twice.)
So let's start by joining the table:
SELECT e.LastName, e.FirstName, e.ReportsTo
FROM Employees e
LEFT OUTER JOIN Employees b on e.ReportsTo = b.ID
The results should still be the same, but now you have more data to select from. So you can add the new columns to the SELECT clause:
SELECT
e.LastName AS EmployeeLastName,
e.FirstName AS EmployeeFirstName,
b.LastName AS BossLastName,
b.FirstName AS BossFirstName
FROM Employees e
LEFT OUTER JOIN Employees b on e.ReportsTo = b.ID
It's a join like any other, it just happens to be a join to the same table.
I'm extremely new to SQL Sever and so I apologize if the question is worded strange. I am doing a homework assignment, and this is the question:
"A manager wants to know the email address, number or orders, and the total amount of purchases made by each customer. Create a summary query that returns these three items for each customer that has orders."
I have all of the data queried, the problem is when I pull data from each customer, it will show the quantity of items per order, and I need the items to be pooled together into one column. This is my query thus far (again, total noob, please excuse any poor syntax, etc.)
SELECT EmailAddress,
ItemPrice - DiscountAmount * Quantity AS TotalPurchaseAmount,
COUNT(*) AS OrderQty
FROM Customers
JOIN Orders ON Customers.CustomerID = Orders.CustomerID
JOIN OrderItems ON Orders.OrderID = OrderItems.OrderID
GROUP BY Orders.CustomerID,
OrderItems.ItemPrice, OrderItems.DiscountAmount,
OrderItems.Quantity,
Customers.EmailAddress;
The following is a small bit of the result set that I get:
Email Address OrderTotal OrderQty
allan.sherwood#yahoo.com 253.15 2
allan.sherwood#yahoo.com 839.30 2
allan.sherwood#yahoo.com 1208.16 2
barryz#gmail.com 303.79 4
christineb#solarone.com 479.60 2
david.goldstein#hotmail.com 299.00 2
david.goldstein#hotmail.com 489.30 1
david.goldstein#hotmail.com 479.60 1
So as you can see, I have several orders I need to smoosh together into one single row per e-mail, I have looked and looked for an answer but the only thing I can find is how to find duplicates and ignore them, not combine their data. Any help is extremely appreciate, thanks so much for taking the time to read this :) If my question doesn't make sense please let me know so I can clear up any bad wording I may have used!
Just do GROUP BY CustomerID, EmailAddress:
SELECT
c.EmailAddress,
SUM((i.ItemPrice - i.DiscountAmount) * Quantity) AS TotalPurchaseAmount,
COUNT(*) AS OrderQty
FROM Customers c
INNER JOIN Orders o
ON c.CustomerID = o.CustomerID
INNER JOIN OrderItems i
ON o.OrderID = i.OrderID
GROUP BY
c.CustomerID, c.EmailAddress
Additional note: Use aliases for your tables
You need to change your formula and remove columns that you dont want to group by from select query..
for example your query should be something like this
SELECT EmailAddress,
--do your aggregation here
blah AS TotalPurchaseAmount,
COUNT(*) AS OrderQty
FROM Customers
JOIN Orders ON Customers.CustomerID = Orders.CustomerID
JOIN OrderItems ON Orders.OrderID = OrderItems.OrderID
GROUP BY Orders.CustomerID,
Customers.EmailAddress;
I have a couple of tables that have data in them that I am looking to get information from. Here is the rundown....In table 1 I have bunch of columns that I am pulling data from, one of the columns is a user ID (which is a number)that was the last userID to modify a record. In table 2 I want to pull in the name of that user based on the ID that is pulled from the other table (this table has both the userID and the username).
so my final query would have the columns in table 1 as well as the username from table 2 to show that was the user to last edit the record. I assume this has to be done in a nested select statement but for the life of me I cannot come up with the correct syntax.
Can anyone help me out?
Thanks
Jeff
Yes, you need a very basic join that link both tables together.
Select t1.UserID,
t2.UserName
FROM table1 t1 INNER JOIN
table2 t2 ON t1.userid=t2.userid
select t1.*, t2.{username} from table1 as t1
join table2 as t2 on t1.{userId}=t2.{userid};
change {username} with the actual column name of user
similarly {userId} with appropriate column name in tables.
Hope it helps you.
this is standard inner join query, to learn more consider reading: http://www.w3schools.com/sql/
Could anyone please explain (or link to a good tutorial) on how to combine data from two tables which is connected with a 'link-table'?
One table contains question
One table contains categories
One table contains question_categories
Each question belongs to many categories, and each category can have many questions.
The link table contain two id's, categoryID and questionID(they are primary keys in the table) with a foreign key to category and question table.
But I do not completely understand how I can write an SQL select that for instance displays what kind of categories question with ID 2 belongs to.
And thorough explanation would be MUCH appreciated!
Thanks in advance.
You use the JOIN clause to connect the tables.
SELECT Q.*
FROM question Q
INNER JOIN question_categories QC
ON q.questionId = QC.questionID
WHERE QC.categoryID = 2
To break it down:
SELECT Q.* -- Get all fields from the alias Q (though you should specify fields)
FROM question Q -- From the question table, aliased Q
INNER JOIN question_categories QC -- Join on the question_categories table (QC)
ON q.questionId = QC.questionID -- Using the questionIds on both tables as join criteria
WHERE QC.categoryID = 2 -- constrain to only categoryId of 2
Edit (example for categories by questionId) as requested in comments:
SELECT C.*
FROM category C
INNER JOIN question_categories QC
ON C.categoryId = QC.categoryID
WHERE QC.questionID = 1