Union All Transformation in SSIS is used to combine data from multiple sources (excel files, flat files, etc.). Or multiple SQL tables and produce one output to store in the destination table. Union All Transformation in SSIS does not follow any particular order while merging the data and storing in the destination table
For example, the company has 100 stores, and each store maintains its sales data. End of the day they all belong to one company and your job is to find out the one month or year sale for any single product. It is not practical to visit 100 stores or to cross-check 100 excel or flat files and calculating the sales. In this situation, all you have to do is, use SSIS Union All Transformation to combine all the 100 excel files from 100 stores and store it in the data warehouse and then calculate the product sales from the database.
NOTE: Union All Transformation in SSIS will produce only one output, and it does not support an error output.
Union All Transformation in SSIS Example
We have product sales data stored in three different excel files (SALES 1, SALES 2, SALES 3, as shown in the below screenshot). And, we want to export all the excel data into one SQL database table.
STEP 1: Drag and drop the data flow task from the toolbox to control flow and rename it as Union All Transformation.
Double click on the SSIS Union All Transformation will take us to the Data flow region.
STEP 2: Drag and Drop three Excel sources from the toolbox to the data flow region
Double click on the first Excel source in the data flow region will open the connection manager settings and provides an option to select the table holding the source data.
From the above screenshot, you can observe that we are selecting SALES 1.xls file as a source. Click ok to select the table or Excel sheet which is holding the data.
Here we selected the LESS_THAN_400 Table present in the Sales1.xls
STEP 3: Click on the columns tab to verify the columns. In this tab, we can uncheck the unwanted columns also.
STEP 4: Double click on second excel source to configure it with Sales 2 excel file.
Do the same for another excel file. Next, Drag and Drop the Union All Transformation into the SSIS data flow region
STEP 5: Join all the Excel sources to the Union All Transformations by dragging the output arrows
STEP 6: Double click on the SSIS Union All Transformation will open Union All Transformation editor window to configure it
TIP: SSIS Union All Transformation editor automatically map columns as long as the column names are the same if they aren’t, then we have to do it manually. Please be careful with the data conversions while working with Excel.
STEP 7: Drag and drop OLE DB destination and double-click on it to configure. Now we have to provide the Server, database, and table details of the target.
Here we selected the SSIS Tutorials database and [Union All Transformation] table as destination.
STEP 8: Click on the Mappings tab to check whether the SSIS Union All Transformation source columns mapped exactly to the destination columns.
By clicking ok we finish developing the Union All Transformation in ssis package So, Let us run the package
Let’s open the SQL Server Management Studio and check the Union All Transformation result