How to apply join on tables while using having function? - sql

There are two tables - trans and customer.
trans
customerid
pdate
purchase
1
11-01-2021
200
2
13-02-2021
400
1
18-01-2021
400
3
31-01-2021
600
4
23-03-2021
700
customer
customerid
firstname
lastname
1
raj
sharma
2
rahul
dev
3
riya
sen
4
rose
menon
The question is -
Find the firstname, lastname and sum of the purchase of the customers where sum of the purchase is greater than 500 in the month of January (Without using any CTE).
My take on this was -
SELECT
c.firstname,
c.lastname,
SUM( t.purchase )
FROM
customer c
INNER JOIN trans t ON c.id = t.id
GROUP BY
c.firstname,
c.lastname
HAVING
SUM( t.purchase ) > 500;
But this ignores the customers with id 1. The customerid 1 has made a purchase twice and the sum of his purchase is greater than 500.
I am using PostgreSQL.

Related

Avoid duplicate values using join with multiple tables in Firebird

I have 3 tables
Payments
PaymntID
Date
Amount
1
Ago.2021
500
2
Sep.2021
1200
3
Oct.2021
600
CashPayments
PaymntID
Amount
1
500
2
400
3
200
CreditCardPayments
PaymntID
Amount
CreditCard
2
450
Visa
2
350
MC
3
400
Visa
I need to get the PaymentID, date, amount payed in cash and amount payed in creditcard, but with the following query I'm getting duplicates.
Just a quick note, I can have two different credit cards used in one payment, but I can also have 2 different "cash payments" used in one payment.
Query:
select
PA.DATE AS PaymntDate,
PA.PaymntID AS PaymntID,
CP.amount AS CashAmount,
CCP.amount AS CreditAmount,
from Payments PA
LEFT join CashPayments CP on PA.PaymntID = CP.PaymntID
LEFT join CreditCardPayments CCP on PA.PaymntID = CCP.PaymntID
I'm getting the following result:
Result
PaymntID
PaymntDate
CashAmount
CreditAmount
1
Ago.2021
500
null
2
Sep.2021
400
450
2
Sep.2021
400
350
3
Oct.2021
200
400
So in this case, the cashpayment in paymntid 2 is duplicated. What I need is the following table:
Result
PaymntID
PaymntDate
CashAmount
CreditAmount
1
Ago.2021
500
null
2
Sep.2021
400
800
3
Oct.2021
200
400
You need to aggregate the values for each ID before joining. Probably the most succinct way is to use a CTE and then outer join each to your payments table, something like the following:
with cp as (
select paymentId, Sum(Amount) Amount
from CashPayments
group by PaymentId
), ccp as (
select paymentId, Sum(Amount) QAmount
from CreditCardPayments
group by PaymentId
)
select p.PaymentId, p.Date,
Coalesce(cp.Amount,0) CashAmount,
Coalesce(ccp.Amount,0) CreditAmount
from Payments p
left join cp on cp.PaymentId = p.PaymentId
left join ccp on ccp.PaymentId = p.PaymentId

SQL Query to get value of recent order alongwith data from other tables

I am writing an SQL query to get data from more than 3 tables, but for simplifying the question here I am using a similar scenario with 3 tables.
Table1 Customer (PK-CustomerID, Name)
CustomerID
Name
1
John
2
Tina
3
Sam
Table2 Sales (FK-Id, SalePrice)
ID
SalePrice
1
200.00
2
300.00
3
400.00
Table3 Order (PK-Id, FK-CustomerID, Date, Amount)
Id
CustomerID
Date
Amount
101
1
25-09-2021
30.0
102
1
27-09-2021
40.0
103
2
19-09-2021
60.0
In the output, Date and Amount should be the from most recent Order (latest Date), for a customer
My approach was
Select c.CustomerID, c.Name, s.SalePrice, RecentOrder.Date, RecentOrder.Amount from
Customer as c
LEFT JOIN Sales s ON c.CustomerID = s.ID
LEFT JOIN (SELECT top 1 o.Date, o.Amount, o.CustomerID
FROM Order o, Customer c1 WHERE c1.CustomerID = o.CustomerID ORDER BY o.Date DESC)
RecentOrder ON c.CustomerID = RecentOrder.CustomerID
Output I get
CustomerID, Name, SalePrice, Date, Amount
CustomerID
Name
SalePrice
Date
Amount
1
John
200.00
27-09-2021
40.0
2
Tina
300.00
null
null
3
Sam
400.00
null
null
The output I get includes the most recent order out of all the orders. But I want to get the recent order out of the orders made by that customer
Output Required
CustomerID, Name, SalePrice, Date, Amount
CustomerID
Name
SalePrice
Date
Amount
1
John
200.00
27-09-2021
40.0
2
Tina
300.00
19-09-2021
60.0
3
Sam
400.00
null
null
Instead of subquery in left join, you can check with outer apply.
Check following way
Select c.CustomerID, c.Name, s.SalePrice, RecentOrder.Date, RecentOrder.Amount
from Customer c
LEFT JOIN Sales s ON c.CustomerID = s.ID
OUTER APPLY (
SELECT top 1 o.Date, o.Amount, o.CustomerID
FROM [Order] o
WHERE o.CustomerID = c.CustomerID ORDER BY o.Date DESC) RecentOrder`
You need to pre-aggregate or identify the most recent order for each customer order, your query is selecting 1 row for all orders.
Try the following (untested!)
select c.CustomerID, c.Name, s.SalePrice, o.Date, o.Amount
from Customer c
left join Sales s on c.CustomerID = s.ID
outer apply (
select top (1) date, amount
from [order] o
where o.CustomerId=c.CustomerId
order by Id desc
)o

Find out the top 3 customers by sum of sales from different groups for the last 30 days - Amazon interview

This was my Amazon SQL interview question which I bombed miserably.
We have 3 tables:
customers orders catalog
cust_id order_date catalog_id
cust_name order_id catalog_name
unit_price cust_id
quantity
catalog_id
The output expected was to find top 3 customers from the 3 catalog / business units for the last 30 days. I tried partitioning over total sales but the last 30 day sales and multiple joins threw me off. Following were the columns requested:
cust_id cust_name catalog_name total_sales(unit_price*quantity)
1 David Books 1400
2 John Books 1200
3 Lisa Books 1000
4 Paul DVDs 500
2 John DVDs 313.5
5 James DVDs 220
6 Alice TV 110
1 David TV 87.5
7 Jerry TV 56
I understand basic 'partitioning over order by' however I have not used it over multiple tables with a datestamp. Kindly help me in understanding this concept. Thank you all in advance!
The query below should give you an idea.
select *
from (select c.cust_id,c.cust_name,ct.catalog_name,sum(o.unit_price * o.quantity) as total_sales,
,dense_rank() over(partition by ct.catalog_name order by sum(o.unit_price * o.quantity) desc) as rnk
from customers c
join orders o on o.cust_id = c.cust_id
join catalog ct on ct.catalog_id = o.catalog_id
--last 30 days filter
where o.order_date >= date_add(day,-30,cast(getdate() as date)) and o.order_date < cast(getdate() as date)
group by c.cust_id,c.cust_name,ct.catalog_name
) t
where rnk <= 3

How get data from 3 tables?

I have 3 tables
collecton, paymentdata, payment
Payment table is computed table and it has only one product data
So, rcvamt and restamt get from payment table
I have following data
Collection:
id(PK) clientid company Client product total note
1 2001 Company1 Client1 Product1 50000 note1
2 2002 Company2 Client2 Product2 60000 note2
3 2003 Company3 Client3 Product3 70000 note3
PaymentData:
wid(PK)wcid(FK) clientid product rcvamt restamt rcvdate nxtdate Note
1 1 2001 Product1 500 49500 10-1-2015 11-2-2015 abc1
2 1 2001 Product1 800 48700 11-2-2015 12-3-2015 xyz1
3 2 2002 Product2 1500 58500 5-3-2015 6-4-2015 qwe1
Payment
id(PK) wid(FK) clientid product rcvamt restamt
1 2 2001 Product1 1300 48700
2 3 2002 Product2 1500 58500
I want to show a report like
clientid company procudt total rcvamt restamt rcvdate nxtdate note
2001 Company1 Product1 50000 1300 48700 11-2-2015 12-3-2015 xyz1
2002 Company2 Product2 60000 1500 58500 5-3-2015 6-4-2015 qwe1
2003 Company3 Product3 70000 - - - - -
I tried to make it simple:
SELECT DISTINCT
C.clientid
, C.company
, C.product
, C.total
, P.rcvamt
, P.restamt
, ( SELECT TOP 1 rcvdate FROM PaymentData AS PD1 WHERE PD1.ClientID=PD.ClientID AND PD1.Product=PD.Product ORDER BY rcvdate DESC)
, ( SELECT TOP 1 nxtdate FROM PaymentData AS PD1 WHERE PD1.ClientID=PD.ClientID AND PD1.Product=PD.Product ORDER BY rcvdate DESC)
, ( SELECT TOP 1 Note FROM PaymentData AS PD1 WHERE PD1.ClientID=PD.ClientID AND PD1.Product=PD.Product ORDER BY rcvdate DESC)
FROM
Collection C
LEFT OUTER JOIN Payment P
ON C.clientid = P.clientid
LEFT OUTER JOIN PaymentData PD
ON P.clientid = PD.clientid
But I don't know all the relationships between the tables.
The Answer to your Question could look like this
Select Collection.clientid
,Collection.company
,Collection.product
,Collection.total
,Payment.rcvamt
,Payment.restamt
,PaymentData.rcvdate
,PaymentData.nxtdate
,PaymentData.Note
From PaymentData
Inner Join (Select wcid
,Max(PaymentData.rcvdate) as rcvdate
,Max(PaymentData.nxtdate) as nxtdate
FROM PaymentData
GROUP BY wcid) AS SubSelect ON PaymentData.wcid = SubSelect.wcid
AND PaymentData.rcvdate = SubSelect.rcvdate
AND PaymentData.nxtdate = SubSelect.nxtdate
Inner Join Payment on PaymentData.wcid = Payment.id
RIGHT OUTER JOIN Collection ON PaymentData.clientid = Collection.clientid
Here the sqlfiddle to prove my Answer.
Something like this should work. It appears you want an aggregation on the restamt, both other fields are the last payment received. I also assume this is SQL Server due to your name. If it's a different db, please provide the
UPDATE: Changed to LEFT JOIN to handle client 3 without products, fixed typo in product. SQL Fiddle: http://sqlfiddle.com/#!3/8ad566/19/0
SELECT
c.clientid,
c.company,
c.product,
c.total,
SUM(pd.rcvamt) AS rcvamt,
LastPayment.restamt,
LastPayment.rcvdate,
LastPayment.nxtDate,
LastPayment.note
FROM Collection c
LEFT OUTER JOIN PaymentData pd
ON pd.wcid = c.id
LEFT OUTER JOIN (
SELECT
wcid,
restamt,
rcvdate,
nxtdate,
Note,
ROW_NUMBER() OVER (PARTITION BY wcid ORDER BY rcvdate DESC) AS RowNum
FROM PaymentData
) LastPayment
ON LastPayment.wcid = c.id
AND LastPayment.RowNum = 1 -- Get last payment info
GROUP BY
c.clientid,
c.company,
c.product,
c.total,
LastPayment.restamt,
LastPayment.rcvdate,
LastPayment.nxtDate,
LastPayment.note
ORDER BY
c.clientid

show result from one table

good day, i have these 3 tables...i.e.;
customer table
cust_id cust_name sales_employee
1 abc 1
2 cde 1
3 efg 2
transaction table
order_num cust_id sales_employee
1001 1 1
1002 2 2
sales_employee table
sales_employee employee name
1 john doe
2 jane doe
how can i show the employee name on both customer table and transaction table?
notice how the sales_employee can change per transaction, it does not necessarily have to be the same per customer.
please help.
To select customers with sales person name
select
C.*, E.employee_name
from
Customers as C
inner join Sales_Employees as E on E.sales_employee = C.sales_employee
To select transactions with customer name and salesperson name (at the point in time of the transaction)
select
T.*,
E.employee_name as Trans_employee,
C.cust_name,
EC.employee_name as Cust_employee
from
Transactions as T
inner join Sales_Employees as E on E.sales_employee = T.sales_employee
inner join Customers as C on C.cust_id= T.cust_id
inner join Sales_Employees as EC on EC.sales_employee = C.sales_employee
This code is meant to guide you, you will need to adjust it to match your table and field names.