Question

I want to do a basic simple data health check across a bunch of table in my DB to present to my users, so I created this:

SELECT
(SELECT COUNT(*) FROM StagingProducts 
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0) AS NumProducts,
(SELECT COUNT(*) FROM StagingCategories 
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0) AS NumCategories,
(SELECT COUNT(*) FROM ManufacturerSalesReps 
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0) AS NumSalesReps,
(SELECT COUNT(*) FROM Orders
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0) AS NumOrders,
(SELECT COUNT(*) FROM StagingCustomers 
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0) AS NumCustomers,
(SELECT COUNT(ItemID) As CategoryItemsCount FROM StagingCategoryItems
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0
   AND ItemID NOT IN (SELECT ItemID FROM StagingProducts WHERE
                      ManufacturerID=@ManufacturerID AND IsDeleted=0)
) AS AbandonedCategoryItemsCount,
(SELECT COUNT(ChildItemID) As ChildCount FROM StagingChildItems
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0
   AND ChildItemID NOT IN (SELECT ItemID FROM StagingProducts WHERE
                           ManufacturerID=@ManufacturerID AND IsDeleted=0)
) AS AbandonedChildCount,
(SELECT COUNT(RelatedItemID) As RelatedCount FROM StagingRelatedItems
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0
 AND RelatedItemID NOT IN (SELECT ItemID FROM StagingProducts WHERE
                           ManufacturerID=@ManufacturerID AND IsDeleted=0)
) AS AbandonedRelatedCount,
(SELECT COUNT(TagID) As RelatedCount FROM StagingTags
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0
   AND ItemID NOT IN (SELECT ItemID FROM StagingProducts WHERE
                      ManufacturerID=@ManufacturerID AND IsDeleted=0)
) AS AbandonedTagCount,
(SELECT COUNT(ItemID) As ModifierItemCount FROM StagingProductModifierLists
 WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0
 AND ItemID NOT IN (SELECT ItemID FROM StagingProducts WHERE
                    ManufacturerID=@ManufacturerID)
) As AbandonedModifierItemCount,
(SELECT COUNT(*) FROM
   (SELECT COUNT(*) AS CNT, CustomerNumber FROM StagingCustomers
    WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0
    GROUP BY CustomerNumber HAVING COUNT(*) > 1
   ) AS DuplicateCustomerCount
) AS DuplicateCustomerCount,
(SELECT COUNT(*) FROM 
   (SELECT COUNT(*) AS CNT, ItemID FROM StagingProducts
    WHERE ManufacturerID=@ManufacturerID AND IsDeleted=0
    GROUP BY ItemID HAVING COUNT(*) > 1
   ) AS DuplicateItemCount
) AS DuplicateItemCount

This can runs super fast sometimes but at other times is just hangs the server. What is the best way for me to approach getting this data from across several tables into a single query?

Answer 1

Since you are touching so many tables in your database and any of these tables can be used while you are running your query, if it’s not super important to get the absolute latest information from your tables, I would use

ALTER PROCEDURE [dbo].[WebManager_DataHealth] @ManufacturerID INT 
AS 
BEGIN
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED
SELECT .....
END