Select most Occurred Value SQL with Inner Join - sql

Question

I am using this query to get the following data from different linked tables. But let's say the VENDORS for an item were three. Now here in result i want to show the Vendor which occurred most. I mean if Item ABC was supplied by 3 different vendors many times. Then here i want to get the Vendor who supplied most of the times item ABC.
My query is this.
use iBusinessFlex;
SELECT Items.Name,
Max(Items.ItemID) as ItemID ,
MAX(Items.Description)as Description,
MAX(ItemsStock.CurrentPrice) as UnitPrice,
MAX(ItemsStock.Quantity) as StockQuantiity,
MAX(Vendors.VendorName) as VendorName,
SUM(ItemReceived.Quantity) as TotalQuantity
From ItemReceived
INNER JOIN Items ON ItemReceived.ItemId=Items.ItemID
INNER JOIN ItemsStock ON ItemReceived.ItemId=ItemsStock.ItemID
INNER JOIN PurchaseInvoices ON PurchaseInvoices.PurchaseInvoiceId = ItemReceived.PurchaseInvoiceId
INNER JOIN Vendors ON Vendors.VendorId = PurchaseInvoices.VendorId
Group By Items.Name
EDIT : I have included this sub query but i am not sure if it is showing correct result. i mean Showing Vendor for each Item who provided that item most of the times
use iBusinessFlex;
SELECT Items.Name,
Max(Items.ItemID) as ItemID ,
MAX(Items.Description)as Description,MAX(ItemsStock.CurrentPrice) as UnitPrice,
MAX(ItemsStock.Quantity) as StockQuantiity,MAX(Vendors.VendorName) as VendorName,
SUM(ItemReceived.Quantity) as TotalQuantity
From ItemReceived
INNER JOIN Items ON ItemReceived.ItemId=Items.ItemID INNER JOIN ItemsStock
ON ItemReceived.ItemId=ItemsStock.ItemID INNER JOIN PurchaseInvoices
ON PurchaseInvoices.PurchaseInvoiceId = ItemReceived.PurchaseInvoiceId INNER JOIN Vendors
ON Vendors.VendorId IN (
SELECT Top 1 MAX(PurchaseInvoices.VendorId) as VendorOccur
FROM PurchaseInvoices INNER JOIN Vendors ON Vendors.VendorId=PurchaseInvoices.VendorId
GROUP BY PurchaseInvoices.VendorId
ORDER BY COUNT(*) DESC
And the Result Looks like this.

Answer 1

First, I would start with who ordered what thing the most. But the MOST is based on what... the most quantity? Price?, Number of Times? If you use one vendor and order 6 times qty of 10 you have 60 things. But order 1 time from another vendor for 100 qty, which one wins. You have to decide the basis of MOST, but I will go based on most times
per your original question.
So all things come from PurchasedInvoices which has a vendor ID. I dont care who the vendor is, just their ID, so no need to join. Also, don't need the item name if I am just looking for my counts. The query below will show per item, each vendor and their respective most times ordered and quantities ordered. I added the items and vendor table joins just to show the names.
select
IR.ItemID,
PI.VendorID,
max( I.Name ) Name,
max( V.VendorName ) VendorName,
count(*) as TimesOrderedFrom,
SUM( IR.Quantity ) as QuantityFromVendor
from
ItemsReceived IR
JOIN PurchaseInvoices PI
on IR.PurchaseInvoiceID = PI.PurchaseInvoiceID
JOIN Items I
on IR.ItemID = I.ItemID
JOIN Vendors V
on IR.VendorID = V.VendorID
group by
IR.ItemID,
PI.VendorID
order by
-- Per item
IR.ItemID,
-- Most count ordered
count(*),
-- If multiple vendors, same count, get total quantity
sum( IR.Quantity )
Now, to get only 1 per item, this would create a correlated subquery and you
can add 'TOP 1' to return only the first by this. Since the aggregate of count
is already done, you can then get the vendor contact info.
select
I.Name,
V.VendorName,
TopVendor.TimesOrderedFromVendor,
TopVendor.QuantityFromVendor
from
Items I
JOIN ( select TOP 1
IR.ItemID,
PI.VendorID,
count(*) as TimesOrderedFrom,
SUM( IR.Quantity ) as QuantityFromVendor
from
ItemsReceived IR
JOIN PurchaseInvoices PI
on IR.PurchaseInvoiceID = PI.PurchaseInvoiceID
where
-- correlated subquery based on the outer-most item
IR.ItemID = I.ItemID
group by
IR.ItemID,
PI.VendorID
order by
-- Per item
IR.ItemID,
-- Most count ordered
count(*),
-- If multiple vendors, same count, get total quantity
sum( IR.Quantity ) ) TopVendor
on I.ItemID = TopVendor.ItemID
JOIN Vendors V
on TopVendor.VendorID = V.VendorID
No sense in having the INNER Subquery joining on the vendor and items just for the names. Get those once and only at the end when the top vendor is selected.