After you've selected the tables you want to include in the export in the previous steps, it's time to select the columns.
- The left column shows all the columns that are part of the tables you selected in the previous step. Select all columns you want to add to the query, and click Add.
- (only applicable if you selected more than 1 column in the previous step)
If you want to use so-called 'Joins' later, which involves linking data from two tables, it is important to have a field with data present in both tables. An example of this in the example above is 'Vendors.VendorsId' and 'VendorContacts.VendorId'; the supplier ID is present in both tables and therefore you can easily link data from both tables.
An example of this is:
The vendor name is only present in the vendor table (Vendors), and not in the vendor contacts table (VendorContacts). Since we want to export a list of supplier contacts including supplier name, we need both tables. The column 'VendorsId' is present in both tables, and we can use that column to place the supplier name from Vendors with the correct contact person from VendorContacts.