Once you create a join, so you can edit it as necessary by creating join conditions.
Open the EDM collaboration file in the EDM Editor.
Right-click the Root Join table on the canvas and then click Edit Join Condition.
The Edit Join Condition window, also called the Condition Builder, appears.
Drag a column from the first table onto the empty canvas on the right.
For this exercise, drag VENDOR from the CUSTOMER_DATA table.
Drag and drop a comparison, string, or another operator onto the canvas to the right of the column name.
For this exercise, use the equal (=) sign.
To add an operator, click the appropriate icon on the toolbar. When the drop-down menu appears, click the icon you want to use and drag it onto the canvas.
Drag a column from the second table onto the canvas to the right of the operator.
For this exercise, drag the VENDOR column from the SUPPLIER_ADDRESS table.
Click OK.
The Edit Join Condition window closes.
Click Save All.
You are now ready to build the Data Mashup project.