Select dialect and version. Paste Local (new/desired) and Origin (old/current). Origin is optional — empty Origin is consolidation mode. Preview parsed schema to see tables and columns the parser produced.
Review detected operations and keep only the changes you want in the generated SQL. Use the parsed schema below if the list looks empty — that can mean the parser dropped objects.
Review the generated statements. Append to Origin DDL to treat the script as already applied, then compare again.