You have a table A with new data, and a table B with old data. How do you make sure table B is refreshed with data from table A? You want to insert new records, update existing records and to delete removed records.
The T-SQL merge statement can do all that for you.
Need to get data from Excel to SQL Server?
Normally this can be achieved by using SSIS. Excel can be used as a source and/or target in a Data flow. But there may be situations where you need more granular control over which data gets imported to SQL Server.
Perhaps there is a process where a user is involved in deciding which data gets inserted to the database, and the import may be initiated be the user. Or maybe some advanced calculations needs to be made to decide which values get inserted.
Anyway, using VBA (Visual Basic for Applications) in Excel macro, it is rather simple to open a connection to a SQL Server database, generate the statements that will select values from the Excel cells and import them to a table. This blog post will show a simple example of how to export data from Excel to SQL Server.
I am using Excel 2013 and SQL Server 2012 in the example.