public SqlExpr createHashExpr(ValueExpr expr)
throws UnsupportedRdbmsOperatorException, RdbmsException
{
result = null;
if (expr == null) {
return new SqlNull();
}
expr.visit(this);
if (unsupported != null) {
throw unsupported(unsupported);
}
if (result == null) {
return new SqlNull();
}
return result;
}