Postgresql – how to add the casting to the following code in SQL

Please do tell me how to get rid of this error

Here is my code:

%%sql 
DROP TABLE IF EXISTS ages;
CREATE TABLE ages AS
SELECT CODEDESC, SUM(age) AS age FROM
(SELECT CODEDESC, (CASE WHEN  (JULIANDAY(MAX(inspdate))-JULIANDAY(MIN(inspdate)))< 30 THEN 30
             ELSE  (JULIANDAY(MAX(inspdate))-JULIANDAY(MIN(inspdate)))
        END)AS age FROM filtered_webextract
INNER JOIN cuisine
ON filtered_webextract.CUISINECODE = cuisine.CUISINECODE
GROUP BY CODEDESC, camis) as foo
GROUP BY CODEDESC;

Here is the error:

 * postgresql://docker:***@nycinspection.tditrain.com:5433/NYCinspection
Done.
(psycopg2.errors.UndefinedFunction) function julianday(timestamp without time zone) does not exist
LINE 3: (SELECT CODEDESC, (CASE WHEN  (JULIANDAY(MAX(inspdate))-JULI...
                                       ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

[SQL: CREATE TABLE ages AS
SELECT CODEDESC, SUM(age) AS age FROM
(SELECT CODEDESC, (CASE WHEN  (JULIANDAY(MAX(inspdate))-JULIANDAY(MIN(inspdate)))< 30 THEN 30
             ELSE  (JULIANDAY(MAX(inspdate))-JULIANDAY(MIN(inspdate)))
        END)AS age FROM filtered_webextract
INNER JOIN cuisine
ON filtered_webextract.CUISINECODE = cuisine.CUISINECODE
GROUP BY CODEDESC, camis) as foo
GROUP BY CODEDESC;]
(Background on this error at: http://sqlalche.me/e/13/f405)

Please let me know how to change my code.
Thanks in advance