Version control practices.vc.html in practical conversion. If a few values of a single property have changed during a new conversion then it is easy to review these changes in a plain-text diff tool.

That works as long as RDF resources are ordered in the same way on each conversion run. Text diff tools do line-by-line comparison, and they are not aware of any RDF semantics. If the order in which RDF resources are saved has changed then text diff tools suddenly become useless: from the line-to-line comparison it looks like every line has changed, while from the RDF perspective the file may remain the same.

A change in the 'WHERE' condition may have dramatic effect on the order in which records are returned.

Best practice here is: sort query results. In this way you will control their ordering.

Both SQL and SPARQL have the ORDER BY statement for that.