Does anyone know what the trick is to deal with trying to combine or compare a free-form text field with a long text field? I can retrieve both, both are text and come out as expected, but if I try to do anything like a

COALESCE(field1, field2) AS thing

or

WHERE field1 = field2

it gives “invalid or unsupported search”

This seems to work

COALESCE(
    TO_CHAR(
      SUBSTR(field1, 1, 4000)
    ),
    field2
  )