SQL Server – How to Get Count of Multiple Tables from Linked and Local Servers

sql server

How can I get records count of multiple tables from linked servers.

I have two servers named production and local. I need to write query to get result as mention in this picture.

I tried

SELECT 'TableA' AS Tables, COUNT(*) AS 'QA' FROM [Database].[schema].[tablename]
UNION
SELECT 'TableB' AS Tables, COUNT(*) AS 'QA' FROM [Database].[schema].[tablename]

How to display records count of linked server?

Best Answer

Use four-part-naming, like this:

SELECT 'TableA' AS Tables
    , COUNT(*) AS 'LinkedServer' FROM [Linked-Server-Name].[Database].[schema].[tablename]
UNION
SELECT 'TableB' AS Tables
    , COUNT(*) AS 'LocalServer' FROM [Database].[schema].[tablename]

Assuming your linked server is named Production, you could use:

SELECT Tables = 'TableA'
    , Production = (SELECT COUNT(*) FROM [Production].[Database].[schema].[tableA])
    , Local = (SELECT COUNT(*) AS FROM [Database].[schema].[tableA])

UNION
    , Tables = 'TableB'
    , Production = (SELECT COUNT(*) FROM [Production].[Database].[schema].[tableB])
    , Local = (SELECT COUNT(*) FROM [Database].[schema].[tableB])

Related Solutions

Sql-server – Query data from multiple linked remote databases

I wrote something a while back, perhaps this link will help you.

http://www.mssqltips.com/sqlservertip/2017/script-to-check-all-your-linked-server-connections-for-sql-server/

I had a need to verify that the linked servers were working, especially after a server rebuild. And I had the same issues you are seeing with regards to using straight t-sql. So I ended up using Powershell in order to get the job done.

HTH

Sql-server – How to query data from a linked server, and pass it parameters to filter by

The performance problem actually had to do with the LEFT OUTER JOIN tables. If I changed them to INNER JOIN, or if I excluded their data from the SELECT columns, the query ran fine.

What I ended up doing was creating a View on the linked server containing all the data I wanted from it, then simply joining to it from the primary server with the #tmpIds table.

I didn't think this would work since I thought joining everything and pulling it down to the second server before filtering was the same as what I was doing now, and would lead to the same performance problem, but surprisingly that doesn't appear to be the case.

CREATE VIEW MyView 
AS

SELECT T1.Id, T2.ColA, ...
FROM Table1 as T1
INNER JOIN Table2 as T2 ON T1.Id = T2.Id
INNER JOIN Table3 as T3 ON T2.Id = T3.Id
LEFT OUTER JOIN Table4 as T4 ON T3.Id = T4.Id
LEFT OUTER JOIN Table5 as T5 ON T4.Id = T5.Id
LEFT OUTER JOIN Table6 as T6 ON T5.Id = T6.Id

GO

and

INSERT INTO #tmpTable (Id, ...)

SELECT T1.Id, T1.ColA, ...
FROM Server.Database.dbo.MyView as T1
INNER JOIN #tmpIds as T ON T1.Id = T.Id

All the joined columns were correctly indexed, however according to this answer

Even though there may be indexing on tables on the remote server, SQL may not be able to take advantage of them while it can build a local query plan that does take advantages of indexing.

And this one

Let the linked server do as much as possible.
It is impossible for SQL Server to optimise a query on a linked server, even another SQL Server

so I am guessing that the query plan used for the query was not using the Indices defined, and SQL Server was generating a poor query plan for the LEFT OUTER JOIN tables.

Best Answer

Related Solutions

Sql-server – Query data from multiple linked remote databases

Sql-server – How to query data from a linked server, and pass it parameters to filter by

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