Update Query with INNER JOIN between tables in 2 different databases on 1 server

Solution 1:

You could call it just style, but I prefer aliasing to improve readability.

UPDATE A    
  SET ControllingSalesRep = RA.SalesRepCode   
from DHE.dbo.tblAccounts A
  INNER JOIN DHE_Import.dbo.tblSalesRepsAccountsLink RA
    ON A.AccountCode = RA.AccountCode

For MySQL

UPDATE DHE.dbo.tblAccounts A 
  INNER JOIN DHE_Import.dbo.tblSalesRepsAccountsLink RA 
      ON A.AccountCode = RA.AccountCode 
SET A.ControllingSalesRep = RA.SalesRepCode

Solution 2:

Following is the MySQL syntax:

UPDATE table1 
INNER JOIN table2 ON table1.field1 = table2.field2
SET table1.field3 = table2.field4 
WHERE ...... ;

http://geekswithblogs.net/faizanahmad/archive/2009/01/05/join-in-sql-update--statement.aspx

Solution 3:

Sorry its late, but I guess it would be of help to those who land here finding a solution to similar problem. The set clause should come right after the update clause. So rearranging your query with a bit change does the work.

UPDATE DHE.dbo.tblAccounts 
SET DHE.dbo.tblAccounts.ControllingSalesRep
    = DHE_Import.dbo.tblSalesRepsAccountsLink.SalesRepCode
from DHE.dbo.tblAccounts 
INNER JOIN DHE_Import.dbo.tblSalesRepsAccountsLink 
    ON DHE.dbo.tblAccounts.AccountCode
        = DHE_Import.tblSalesRepsAccountsLink.AccountCode