SQL Data Compare can compare similar data types, however, there is a risk of truncation in some cases.
When comparing between data between source and target, it is important that the data types are comparable. The table below shows which data types can be compared:
If the data types are not comparable, then SQL Data Compare will be unable to complete the comparison which will result in the following exception or similar:
"Unable to compare between fields <field> and <field>, types being compared <data type> and <data type>. Inner ArgumentException: Object must be of <data type>"
To resolve this issue, you must either change the datatype or cast into a view.