Here are the tables
Customer (Id, Name, Address, City, State, Zip)
Account (Id, CustomerID, OpenDate, CloseDate, Type, Balance)
Transaction (Id, AccountId, Amount, BranchId...)
Branch (Id, Name, Address, City, State, Zip)
And the question goes: List the names of the customers who made transactions of an amount exceeding $100 any bank branch in Seattle.
I am thinking about something like this, but I am not sure how to do the rest from here:
SELECT Name
FROM Customer c
JOIN Account a ON a.CustomerID = c.Id
JOIN
Please help, Thank you!!
SELECT c.Name FROM Customer c INNER JOIN Account a ON c.Id = a.CustomerID INNER JOIN TRANSACTION t on t.AccountId = a.Id INNER JOIN BRANCH b ON t.BranchID = b.Id WHERE t.AMOUNT > 100 AND t.branch = "Seattle"
Related
I'm very new to learning SQL, I apologize if my question isn't completely accurate.
The question I'm trying to answer with this query is "What is the most popular music genre in each country?" I've had to use a subquery and it works, but I found that for a few countries in the table, more than one genre has the MAX value. I'm stuck with how to edit my query so that all genres with the max value show in the results. Here is my code, using DB Browser for SQLite:
SELECT BillingCountry AS Country , name AS Genre , MAX(genre_count) AS Purchases
FROM (
SELECT i.BillingCountry, g.name, COUNT(g.genreid) AS genre_count
FROM Invoice i
JOIN InvoiceLine il
ON il.InvoiceId = i.InvoiceId
JOIN TRACK t
ON il.trackid = t.TrackId
JOIN Genre g
ON t.genreid = g.GenreId
GROUP BY 1,2
) sub
GROUP BY 1
Here is an example of the result:
| Country | Genre |Purchase|
|---------|-------|--------|
|Agrentina| Punk | 9 |
|Australia| Rock | 22 |
BUT in running just the subquery to COUNT the purchases, Argentina has two Genres with 9 Purchases (the max number for that country). How do I adjust my query to include both and not just the first one in the row?
You can do it with RANK() window function:
SELECT BillingCountry, name, genre_count
FROM (
SELECT i.BillingCountry, g.name, COUNT(*) AS genre_count,
RANK() OVER (PARTITION BY i.BillingCountry ORDER BY COUNT(*) DESC) rnk
FROM Invoice i
INNER JOIN InvoiceLine il ON il.InvoiceId = i.InvoiceId
INNER JOIN TRACK t ON il.trackid = t.TrackId
INNER JOIN Genre g ON t.genreid = g.GenreId
GROUP BY i.BillingCountry, g.name
)
WHERE rnk = 1
This will return the ties in separate rows.
If you want 1 row for each country, you could also use GROUP_CONCAT():
SELECT BillingCountry, GROUP_CONCAT(name) AS name, MAX(genre_count) AS genre_count
FROM (
SELECT i.BillingCountry, g.name, COUNT(*) AS genre_count,
RANK() OVER (PARTITION BY i.BillingCountry ORDER BY COUNT(*) DESC) rnk
FROM Invoice i
INNER JOIN InvoiceLine il ON il.InvoiceId = i.InvoiceId
INNER JOIN TRACK t ON il.trackid = t.TrackId
INNER JOIN Genre g ON t.genreid = g.GenreId
GROUP BY i.BillingCountry, g.name
)
WHERE rnk = 1
GROUP BY BillingCountry
I have three tables that I would like to select from
Table 1 has a bunch of static information about a user like their idnumber, name, registration date
Table 2 has the idnumber of the user, course number, and the date they registered for the course
Table 3 has the course number, and the title of the course
I am trying to use one query that will select the columns mentioned in table 1, with the most recent course they registered (name and date registered) as well as their first course registered (name and date registered)
Here is what I came up with
SELECT u.idst, u.userid, u.firstname, u.lastname, u.email, u.register_date,
MIN(l.date_inscr) as mindate, MAX(l.date_inscr) as maxdate, lc.coursename
FROM table1 u,table3 lc
LEFT JOIN table2 l
ON l.idCourse = lc.idCourse
WHERE u.idst = 12787
AND u.idst = l.idUser
And this gives me everything i need, and the dates are correct but I have no idea how to display BOTH of the names of courses. The most recent and the first.
And help would be great.
Thanks!!!
You can get your desired results by generating the min/max date_inscr for each user in a derived table and then joining that twice to table2 and table3, once to get each course name:
SELECT u.idst, u.userid, u.firstname, u.lastname, u.email, u.register_date,
l.mindate, lc1.coursename as first_course,
l.maxdate, lc2.coursename as latest_course
FROM table1 u
LEFT JOIN (SELECT idUser, MIN(date_inscr) AS mindate, MAX(date_inscr) AS maxdate
FROM table2
WHERE idUser = 12787
) l ON l.idUser = u.idst
LEFT JOIN table2 l1 ON l1.idUser = l.idUser AND l1.date_inscr = l.mindate
LEFT JOIN table3 lc1 ON lc1.idCourse = l1.idCourse
LEFT JOIN table2 l2 ON l2.idUser = l.idUser AND l2.date_inscr = l.maxdate
LEFT JOIN table3 lc2 ON lc2.idCourse = l2.idCourse
As #BillKarwin pointed out, this is more easily done using two separate queries.
This is based on a Khan Academy course. I have 2 SQLite tables:
CREATE TABLE table1 (id STRING PRIMARY KEY, charge_id TEXT, amount INTEGER, currency INTEGER, country STRING);
INSERT INTO table1
( id, charge_id, amount, currency, country) VALUES
('0xb01', '0x1', 2000, 'USD', 'USA'),
('0x0a1', '0x1', 500, 'USD', 'USA'),
('0x0c1', '0x1', 1000, 'CAD', 'USA'),
('0xs31', '0x4', 1000, 'YEN', 'CA');
CREATE TABLE table2 (id STRING PRIMARY KEY, charge_id TEXT, value VARIABLE);
INSERT INTO table2
( id, charge_id, value ) VALUES
('0x34s', '0x1', '123 main street'),
('0x3ze', '0x1', 'merchant-id-001'),
('0x3w2', '0x2', 'zip-code-90210' ),
('0x35k', '0x2', 'merchant-id-002');
I would SELECT the amount, currency and country from table 1 (Charges) and join with table 2 (Metadata) based on the id. Charges uses ID, while Metadata stores meta tags, with a unique identifier [id] equal to the charge [id] from Charges. I want to group the total amount, total currency for each merchant_id and only those charges that were made in the USA.
Step-by-step pseudo code:
(1) find all charges in the USA (Charges country)
(2) match all charge_ids from Charges (id) to charges in Metadata (id)
(3) separate each charge by the merchant_id (Metadata value)
(4) display the total amount, currency by merchant_id (amount, Charges currency, value)
This is a difficult because :
(1) I want to select from Charges and
(2) join to Metadata by the [id]
(3) but each Metadata record only has the charge_id and a metadata tag, which would match the merchant_id with the charge
The query result I would like is:
value (merchant id) currency total amount
merchant-id-001 usd 2500
merchant-id-001 cad 1000
merchant-id-002 yen 200
merchant-id-002 cad 50
Currently I have this query but it does not seem to be working:
select table1.amount, table1.currency, table1.country, count(*)
from table1
LEFT JOIN table1
UNION ALL
SELECT table2.value
FROM CHARGES_table2
LEFT JOIN table2
ON table1.id = table2.id
WHERE table1.country = 'USA'
GROUP BY table2.value
I am getting errors on union parameters: 2,1
Read the grammar & other documentation for the expressions you are using. The arguments to UNION are two SELECTs & it can have a final ORDER BY. Here's the parse:
select table1.amount, table1.currency, table1.country, count(*)
from table1
LEFT JOIN table1
UNION ALL
SELECT table2.value
FROM CHARGES_table2
LEFT JOIN table2
ON table1.id = table2.id
WHERE table1.country = 'USA'
GROUP BY table2.value
UNION is putting its arguments' rows into one table so it also requires that their columns agree in number & have compatible types. Here the numbers disagree.
There is no table1 in scope in the second SELECT so that is an error in isolation that is moot given the UNION.
If I have a model that has several tables, and I am joining these tables together into a flat table within my controller class, how do I get the view to be able to access the flat table?
For example, let's say I have three tables in my model (customers, orders, invoices).
Orders are linked to customer by a foreign key (CustomerID), and invoices are linked to orders by a foreign key (OrderID).
In order to see all of this in one flat table (with all customers listed, even if they don't have orders, and all orders listed, even if they don't have invoices), I have the following anonymous type:
var FlatTable = (from a in customers
let CustomerID = a.ID
join b in orders on a.ID equals b.CustomerID into ab
from b in ab.DefaultIfEmpty()
let OrderID = b.ID
join c in invoices on b.ID equals c.InvoiceID into ac
from c in ac.DefaultIfEmpty()
let InvoiceID = c.ID
select new {a.CustomerName, CustomerID, OrderID, b.ProductDescription, InvoiceID, c.InvoiceAmount});
return View(FlatTable.ToList());
Then in my View (which is based on my model), how am I able to access FlatTable.
IList<ViewModel> model = (from a in customers
join b in orders on a.ID equals b.CustomerID into ab
from b in ab.DefaultIfEmpty()
join c in invoices on b.ID equals c.InvoiceID into ac
from c in ac.DefaultIfEmpty()
select new ViewModel() {CustomerName = a.CustomerName, CustomerID = a.ID, OrderID = b.ID, ProductDescription = b.ProductDescription, InvoiceID = c.ID, InvoiceMaount = c.InvoiceAmount}).ToList();
I have two tables named "likes" and "comments" and I want to have a table which has counts of likes and comments for each specific user, I wrote following query in SQLite but result is not true for all users, count values for users in both tables are multiple of number of likes and number of comments.
SELECT
likes.liker_name, likes.liker_id, likes.profile_picture ,
COUNT(comments.commenter_name) AS comment_count, COUNT( likes.liker_id) AS like_count
FROM likes
LEFT JOIN comments
ON likes.liker_name = comments.commenter_name
GROUP BY
likes.liker_name
ORDER BY
COUNT( likes.liker_id) DESC
How can I get correct value of count for users that exist in both tables?
The problem is: Some users have comments but no likes, others have likes but no comments, some have both and some have none. Therefore I suggest using a union query and summing that one again
SELECT
u.name, u.id, u.profile_picture,
SUM(u.like_count) AS like_count, SUM(u.comment_count) AS comment_count
FROM (
SELECT
liker_name AS name, liker_id AS id, profile_picture,
COUNT(*) AS like_count, 0 AS comment_count
FROM
likes
GROUP BY
liker_name, liker_id, profile_picture
UNION ALL
SELECT
commenter_name AS name, commenter_id AS id, profile_picture,
0 AS like_count, COUNT(*) AS comment_count
FROM
comments
GROUP BY
commenter_name, commenter_id, profile_picture
) AS u
GROUP BY
u.name, u.id, u.profile_picture
If you have a separate user table you could also left join the likes count and the comments count subqueries to the user table
SELECT
u.name, u.id, u.profile_picture, l.cnt AS like_count, c.cnt AS comment_count
FROM
users u
LEFT JOIN
(SELECT liker_id, COUNT(*) AS cnt
FROM likes
GROUP BY liker_id
) AS l
ON u.user_id = l.liker_id
LEFT JOIN
(SELECT commenter_id, COUNT(*) AS cnt
FROM comments
GROUP BY commenter_id
) AS c
ON u.user_id = c.commenter_id
WHERE l.cnt > 0 OR c.cnt > 0
No matter how you make it, you must count the comments and the likes in separate subqueries. If you count after joining you are summing on a result where records might be duplicated (the ones on the left side) and you are getting the wrong count.