I have created a very simple dashboard, with Superset 3.0.1. It works perfectly and you can see the query that is made in the screenshot on the left. I show the query that is executed below:

SELECT anon_1."ID_TYPE_ACCESS"
DESDE
 (SELECT "ID_TYPE_ACCESS" AS "ID_TYPE_ACCESS"
 FROM f_matricula
 GROUP BY "ID_TYPE_ACCESS") anon_1
WHERE ROWNUM <= 1000;

I have configured the superset embedding, I have developed a backend in Java + Tomcat to retrieve the guestToken and I have created an html file with an iframe to load the dashboard.

When I try to view the dashboard through my html file, Superset responds with an “Unexpected error”: “Error: ORA-00920: invalid relational operator.” The query that is executed can be seen in the screenshot on the right. I write it below.

SELECT anon_1."ID_TIPO_ACCESO"
FROM
  (SELECT "ID_TIPO_ACCESO" AS "ID_TIPO_ACCESO"
   FROM dm_academico.f_matricula
   WHERE (string)
   GROUP BY "ID_TIPO_ACCESO") anon_1
WHERE ROWNUM <= 1000;

For some reason, a “where (string)” is added when I load the dashboard through my iframe. If I run this query removing the “where (string)” in SqlDeveloper it works perfectly.
I attached an image of this. On the left the dashboard executed on Superset, on the right my html.
superset and html file
Has something similar happened to you? Can you think of what could be happening?
Thank you very much, any idea will be welcome.