if (rightDatatype != null) { result = compareDatatypes(leftDatatype, rightDatatype);
if (rightDatatype != null) { result = compareDatatypes(leftDatatype, rightDatatype);
if (rightDatatype != null) { result = compareDatatypes(leftDatatype, rightDatatype);
if (rightDatatype != null) { result = compareDatatypes(leftDatatype, rightDatatype);