This dialog is opened using Custom data diff toolbar action and allows to specify custom column mappings for keys and comparable columns:
This dialog is also opened with Column mapping action from Data diff and Query result diff tab. For Query result diff this dialog is also opened when you specify Customize key & data column mapping option. In both Data diff and Query result diff this dialog is opened without Left table / Right table at the top because it is already defined by application usage context: for Data diff you process some concrete table/view, for Query result diff you have already defined arbitrary query text.
At least one mapping item must be specified as a Key and this column (or column combination) must be unique across all rows on each side.
Free version limitations:
Last updated: 2019-07-25