Oracle database error 907: ORA-00907: missing right parenthesis - sql

Question

I transferred this code directly from SQL developer. Works perfectly in there.
SELECT
a.INCIDENT_NUMBER,
a.DETAILED_DESCRIPTION,
a.INCIDENT_ROOT_CAUSE
FROM
N_EVALUATION as a
INNER JOIN N_DISPOSITION as b
ON (a.INCIDENT_NUMBER = b.INCIDENT_NUMBER)
WHERE
b.DISPOSITION_LINE_NUM in (NULL, 1) AND
a.ACTIVE_FLAG = 'Y' AND
b.ACTIVE_FLAG = 'Y' AND
a.DETAILED_DESCRIPTION IS NOT NULL
However when I transfer the same exact code into Tableau to create a custom SQL query. It gives me an error;
An error occurred while communicating with the data source. Bad
Connection: Tableau could not connect to the data source. Oracle
database error 907: ORA-00907: missing right parenthesis
This has me completely stumped, not really sure what to do here. Any help or advice is much appreciated. I am more concerned regarding the missing right parenthesis rather than the bad connection.

Answer 1

Remove the AS from the FROM clause. Oracle does not recognize that.
In addition, this condition:
b.DISPOSITION_LINE_NUM in (NULL, 1)
Does not do what you expect. It never evaluates to true if b.DISPOSITION_LINE_NUM is NULL.
You should replace it with:
(b.DISPOSITION_LINE_NUM IS NULL OR b.DISPOSITION_LINE_NUM = 1)
Otherwise, your query looks like it has balanced parentheses, but you should write it as:
SELECT e.INCIDENT_NUMBER, e.DETAILED_DESCRIPTION, e.INCIDENT_ROOT_CAUSE
FROM N_EVALUATION e JOIN
N_DISPOSITION d
ON e.INCIDENT_NUMBER = d.INCIDENT_NUMBER
WHERE (d.DISPOSITION_LINE_NUM IS NULL OR d.DISPOSITION_LINE_NUM = 1) AND
e.ACTIVE_FLAG = 'Y' AND
d.ACTIVE_FLAG = 'Y' AND
e.DETAILED_DESCRIPTION IS NOT NULL;
Notes:
User meaningful table aliases rather than arbitrary letters (this uses abbreviations).
Do not use as in the FROM clause.
Be careful with NULL comparisons.
Finally, your original query is equivalent to:
SELECT e.INCIDENT_NUMBER, e.DETAILED_DESCRIPTION, e.INCIDENT_ROOT_CAUSE
FROM N_EVALUATION e JOIN
N_DISPOSITION d
ON e.INCIDENT_NUMBER = d.INCIDENT_NUMBER
WHERE d.DISPOSITION_LINE_NUM = 1 AND
e.ACTIVE_FLAG = 'Y' AND
d.ACTIVE_FLAG = 'Y' AND
e.DETAILED_DESCRIPTION IS NOT NULL;
This has no parentheses. So it cannot return that particular error.