The database is being transferred to a new SQL Server, where disk storage costs pennies for the gigabyte, and relational architecture reigns supreme. These composite columns present a challenge, because only a portion of their value must be used to join another table -- not exactly something that Query Builder can handle.
The following Orders and Products tables must be joined. The middle 3 digits of Orders.InvoiceNumber match Customers.CustomerId:
CREATE TABLE [dbo].[Orders]( [OrderId] [int] NOT NULL, [InvoiceNumber] [varchar(50)] NOT NULL, [OrderDate] [datetime] NOT NULL) CREATE TABLE [dbo].[Customers]( [CustomerId] [int] NOT NULL, [CustomerName] [varchar](50) NOT NULL)
To join these tables, we simply use the SUBSTRING() method, to extract the middle 3 characters of InvoiceNumber. The resulting Varchar typed data may then be implicitly cast to int:
SELECT * FROM Orders o INNER JOIN Customers c ON CAST(SUBSTRING(o.InvoiceNumber, 4, 3) AS int) = c.CustomerId
As always, I recommend saving queries as stored procedures, to leverage the security and performance benefits of calling pre-compiled code.