`NewDiffTable` uses the root table schema as both the before and after schema when creating the `dolt_diff` schema ([code](https://github.com/dolthub/dolt/blob/6e9d403257b39a3e6e29bd5200c732e2d4611bfe/go/libraries/doltcore/sqle/dtables/diff_table.go#L106)) This will yield an inaccurate diff if columns have been added or deleted.
NewDiffTableuses the root table schema as both the before and after schema when creating thedolt_diffschema (code)This will yield an inaccurate diff if columns have been added or deleted.