I have a view like that:
create view dbo.VEmployeeSalesOrders
as
select
employees.employeeID, Products.productID,
Sum(Price * Quantity) as Total,
salesDate,
COUNT_BIG() as [RecordCount]
from
dbo.Employees
inner join
dbo.sales on employees.employeeID = sales.employeeID
inner join
dbo.products on sales.productID = products.ProductID
group by
Employees.employeeID, products.ProductID, salesDate
When I select * from dbo.VEmployeeSalesOrders it takes 97% of the execution plan. It needs it to be faster.
And when I try to create an index, an exception fires with the following message:
select list doesn't include a proper use on count_Big()
Why am getting this error?
1-first you need to alter your view and make it contains COUNT_BIG() function because you used aggregate function in select statment,
AND THE REASON FOR USING THAT is that SQL Server needs to track the record where the record is ,number of records
like this
create view dbo.VEmployeeSalesOrders
as
select employees.employeeID,Products.productID,Sum(Price*Quantity)
as Total,salesDate,COUNT_BIG(*) as [RecordCount]
from dbo.Employees
inner join dbo.sales on employees.employeeID=sales.employeeID
inner join dbo.products on sales.productID-products.ProductID
group by Employees.employeeID,products.ProductID,salesDate
2- then you need to create index like that
Create Unique Clustered Index Cidx_IndexName
on dbo.VEmployeeSalesOrders(employedID,ProductID,SalesDate)
Hope It Works
Related
I have a job I need to automate to make sure a cache for some entities in my database is populated. I have the query below using CTE and CROSS JOIN but it doesn't run very quickly so I'm sure it can be improved.
The issue:
I have a database of employees
Each employee has a report of data compiled each month.
Each report has a set of 'components' and each of those components 'data' is pulled from an external source and cached in my database
The goal:
I want to set up a job to take a group of component Ids for 'this months report' and pre-cache the data if it doesn't exist.
I need to get a list of employees and the components they are missing in the cache for this months report. I will then set up a CRON job to process the queue.
The Question
My query below is slow - Is there a more efficient way to return a list of employees and the component ids that are missing in the cache?
The current SQL:
declare #reportDate datetime2 = '2019-10-01'; //the report publish date
declare #componentIds table (id int); // store the ids of each cachable component
insert #componentIds(id) values(1),(2),(3),(4),(5);
;WITH cteCounts
AS (SELECT r.Id as reportId, cs.componentId,
COUNT(1) AS ComponentCount
FROM EmployeeReports r
LEFT OUTER JOIN CacheStore cs on r.Id = cs.reportId and cs.componentId in (SELECT id FROM #componentIds)
GROUP BY r.Id, cs.componentId)
SELECT e.Id, e.name, _c.id as componentId, r.Id as reportId
FROM Employees e
INNER JOIN EmployeeReports r on e.Id = r.employeeId and r.reportDate = #reportDate
CROSS JOIN #componentIds _c
LEFT OUTER JOIN cteCounts AS cn
ON _c.Id = cn.componentId AND r.Id = cn.reportId
WHERE cn.ComponentCount is null
2 things I can suggest doing:
Use NOT EXISTS instead of a LEFT JOIN + IS NULL. The execution plan is prone to be different when you tell the engine that you want records that don't have any occurrence in a particular set Vs. joining and making sure that the joined column is null.
SELECT e.Id, e.name, _c.id as componentId, r.Id as reportId
FROM Employees e
INNER JOIN EmployeeReports r on e.Id = r.employeeId and r.reportDate = #reportDate
CROSS JOIN #componentIds _c
WHERE
NOT EXISTS (SELECT 'no record' FROM cteCounts AS cn
WHERE _c.Id = cn.componentId AND r.Id = cn.reportId)
Use temporary tables instead of CTE and/or variable tables. If you have to handle many rows, variable tables don't actually have statistics on and some complex CTE's might actually make lousy execution plans. Try using temporary tables instead of these 2 and see if the performance boosts. Also try creating relevant indexes on them if your row count is high.
Does JOINING of tables more easy to read or faster to execute if I create a sub query and a select statement with only the columns needed for the entire query?
-- Example
SELECT s.Id,
s.TransactionDate,
s.TransactionNo,
s.CustomerId,
s.SiteLocationId,
s.SubTotal,
sd.ItemId,
sd.UnitPrice,
sd.GrossAmount
FROM tblTransactions s
LEFT OUTER JOIN tblTransactionDetails sd ON sd.TransactionId = s.Id
Compare to this:
SELECT s.Id,
s.TransactionDate,
s.TransactionNo,
s.CustomerId,
s.SubTotal,
sd.ItemId,
sd.UnitPrice,
sd.GrossAmount
FROM tblTransactions s
LEFT OUTER JOIN (
SELECT TransactionId,
ItemId,
UnitPrice,
GrossAmount
FROM tblTransactionDetails
) sd ON sd.TransactionId = s.Id
What are the advantages and disadvantages of each example given? I am also trying to reduce the percentage read of the Details in the Execution Plan.
I think that SQL Server creates the same execution plan for both queries. If you want to increase the performance due to the column selection, you should create a non-clustered index. Then, the query optimizer should use the more compact index instead the table.
CREATE NONCLUSTERED INDEX ix_tblTransactionDetails_test
ON tblTransactionDetails (TransactionId) INCLUDE (ItemId, UnitPrice, GrossAmount)
Need to build a temporary table or a CTE for reporting purposes. Users will be able to select a location and courses from drop-downs.
The tables involved are the Person table that holds all employees and a Common Table Expression that will have the courses selected from drop down.
I need to be able to create a temporary table or a CTE with employee id field from the person table and a course name field from Course CTE.
For example, if courses A, B, C are selected each employee will have three records, one for each Course selected. So employee 1 will have three records in this temporary table or CTE. I'm using SQL Server 2008.
You can use INNER JOIN or UNION queries inside CTE to get values from Multiple Tables. So If you want to get the EMployeeId and CourseName for Each employee, YOu can Join the tables inside the CTE like this
;WITH CTE
AS
(
SELECT
E.EmployeeId,
C.CourseNm
FROM dbo.Employee E
INNER JOIN dbo.Course C
ON E.CourseId = C.CourseId
)
SELECT
*
FROM CTE
if you want to use Temp tables, you can try this
SELECT
E.EmployeeId,
C.CourseNm
INTO #Temp
FROM dbo.Employee E
INNER JOIN dbo.Course C
ON E.CourseId = C.CourseId
SELECT * FROM #Temp
I am running a query that returns records from the LEFT of the EXCEPT that are not on the right query;
USE AdventureWorks;
GO
SELECT ProductID
FROM Production.Product
EXCEPT
SELECT ProductID
FROM Production.WorkOrder;
Lets say there are 6 records returned (there are 6 records in Production.Product table, that are not in Production.WorkOrder)
How would I write the query to update the 6 records into Production.WorkOrder table?
insert into workorder (productid)
select productid from product where productid not in (select productid from workorder)
This will insert into workorder all the productid's in the product table that aren't already in workorder.
I'd use a left join, like this:
USE AdventureWorks;
GO
SELECT p.ProductID
FROM Production.Product p
LEFT
JOIN Production.WorkOrder wo
ON p.ProductID = wo.ProductID
WHERE wo.ProductID IS NULL;
This will return all the ProductID values from Product that do not appear in WorkOrder. The problem with the other answer (WHERE NOT IN) is that the sub-query will execute once/row, and if the tables are large, this will be really slow. A LEFT JOIN will only execute once, and then SQL will match the rows up - on a small table, there won't be much difference in practice, but on a larger table or in a production database, the difference will be immense.
Just turn your query into an INSERT?
INSERT INTO Production.WorkOrder(ProductID, ...)
SELECT ProductID, ...
FROM Production.Product
EXCEPT
SELECT ProductID
FROM Production.WorkOrder;
I have two tables:
**Product**
ID
Name
SKU
**Brand**
ID
Name
Product table has about 120K records
Brand table has 30K records
I need to find count of all the products with name and brand matching a specific keyword.
I use freetext 'contains' like this:
SELECT count(*)
FROM Product
inner join Brand
on Product.BrandID = Brand.ID
WHERE (contains(Product.Name, 'pants')
or
contains(Brand.Name, 'pants'))
This query takes about 17 secs.
I rebuilt the FreeText index before running this query.
If I only check for Product.Name. They query is less then 1 sec. Same, if I only check the Brand.Name. The issue occurs if I use OR condition.
If I switch query to use LIKE:
SELECT count(*)
FROM Product
inner join Brand
on Product.BrandID = Brand.ID
WHERE Product.Name LIKE '%pants%'
or
Brand.Name LIKE '%pants%'
It takes 1 secs.
I read on MSDN that: http://msdn.microsoft.com/en-us/library/ms187787.aspx
To search on multiple tables, use a
joined table in your FROM clause to
search on a result set that is the
product of two or more tables.
So I added an INNER JOINED table to FROM:
SELECT count(*)
FROM (select Product.Name ProductName, Product.SKU ProductSKU, Brand.Name as BrandName FROM Product
inner join Brand
on product.BrandID = Brand.ID) as TempTable
WHERE
contains(TempTable.ProductName, 'pants')
or
contains(TempTable.BrandName, 'pants')
This results in error:
Cannot use a CONTAINS or FREETEXT predicate on column 'ProductName' because it is not full-text indexed.
So the question is - why OR condition could be causing such as slow query?
After a bit of trial an error I found a solution that seems to work. It involves creating an indexed view:
CREATE VIEW [dbo].[vw_ProductBrand]
WITH SCHEMABINDING
AS
SELECT dbo.Product.ID, dbo.Product.Name, dbo.Product.SKU, dbo.Brand.Name AS BrandName
FROM dbo.Product INNER JOIN
dbo.Brand ON dbo.Product.BrandID = dbo.Brand.ID
GO
CREATE UNIQUE CLUSTERED INDEX IX_VW_PRODUCTBRAND_ID
ON vw_ProductBrand (ID);
GO
If I run the following query:
DBCC DROPCLEANBUFFERS
DBCC FREEPROCCACHE
GO
SELECT count(*)
FROM Product
inner join vw_ProductBrand
on Product.BrandID = vw_ProductBrand.ID
WHERE (contains(vw_ProductBrand.Name, 'pants')
or
contains( vw_ProductBrand.BrandName, 'pants'))
It now takes 1 sec again.
I ran into a similar problem but i fixed it with union, something like:
SELECT *
FROM Product
inner join Brand
on Product.BrandID = Brand.ID
WHERE contains(Product.Name, 'pants')
UNION
SELECT *
FROM Product
inner join Brand
on Product.BrandID = Brand.ID
WHERE contains(Brand.Name, 'pants'))
Have you tried something like:
SELECT count(*)
FROM Product
INNER JOIN Brand ON Product.BrandID = Brand.ID
WHERE CONTAINS((Product.Name, Brand.Name), 'pants')