Invalid number exception when using CASE in view? - jdbc

Question

There is a table called USER_SETUP. This table has a column called EMPLOYEE_ID which is originally VARCHAR. I created a view to convert the VARCHAR data type to NUMBER. I used TO_DECIMAL("EMPLOYEE_ID",12,0) AS "EMPLOYEE_ID" (because when I use TO_INTEGER("EMPLOYEE_ID") AS "EMPLOYEE_ID", I am getting exception in view).
The view is created using nested SQL statement [e.g: select * from (select * from table)] The view is generating correct output with correct data. In the view I created 2 columns using CASE function which is based on the SQL code inside. Refer the code of SQL View below
Main View code:
CREATE VIEW ECLINIC_KNG.VIEW_USER_SETUP AS
SELECT
USER_ID,
EMPLOYEE_ID,
CASE
WHEN EMPLOYEE_ID < 50000 THEN 'Kuwaiti'
WHEN EMPLOYEE_ID >= 50000 AND LENGTH(EMPLOYEE_ID) <=6 THEN 'Non-Kuwaiti'
ELSE 'NOT KNG'
END AS "KWT_NKWT",
CASE
WHEN LENGTH(EMPLOYEE_ID) <=6 THEN 'KNG'
WHEN LENGTH(EMPLOYEE_ID)=12 THEN 'MOH'
ELSE 'Undefined'
END AS "KNG_MOH",
USER_NAME,
ACTIVE_DATE,
DEACTIVE_DATE,
ACTIVE_STATUS,
USER_CODE,
USER_LABEL,
USER_PASSWORD,
USER_TYPE,
OFFICE_ID,
USER_DESIG,
USER_LICENSE,
USER_SIGN,
CLIMIT_DAYS,
EDIT_BILL_SERVICE,
PASSWORDGROUP_ID,
USERLABEL_AR,
DISCOUNT_APPROVAL,
DISCOUNT_TYPE,
DISCOUNT_MAX,
BILL_CANCELLATION,
BILL_CANCELLATION_DAYS,
DOCTOR_ID
FROM
(SELECT
"USER_ID",
--TO_INTEGER("EMPLOYEE_ID") AS "EMPLOYEE_ID" ,
TO_DECIMAL("EMPLOYEE_ID",12,0) AS "EMPLOYEE_ID",
"USER_NAME",
"ACTIVE_DATE",
"DEACTIVE_DATE",
"ACTIVE_STATUS",
"USER_CODE",
"USER_LABEL",
"USER_PASSWORD",
"USER_TYPE",
"OFFICE_ID",
"USER_DESIG",
"USER_LICENSE",
"USER_SIGN",
"CLIMIT_DAYS",
"EDIT_BILL_SERVICE",
"PASSWORDGROUP_ID",
"USERLABEL_AR",
"DISCOUNT_APPROVAL",
"DISCOUNT_TYPE",
"DISCOUNT_MAX",
"BILL_CANCELLATION",
"BILL_CANCELLATION_DAYS",
"DOCTOR_ID"
FROM
"ECLINIC_KNG"."USER_SETUP"
WHERE
"USER_SETUP"."EMPLOYEE_ID" not in ('undefined', '299450','34(NEW RECRUIT)', 'army', 'MOH
Nurse','NEW RECRUITMENT 380','1111111','0')
AND
"USER_SETUP"."EMPLOYEE_ID" LIKE_REGEXPR '[0-9]'
ORDER BY
"USER_ID");
The 2 new columns created in the view
CASE
WHEN EMPLOYEE_ID < 50000 THEN 'Kuwaiti'
WHEN EMPLOYEE_ID >= 50000 AND LENGTH(EMPLOYEE_ID) <=6 THEN 'Non-Kuwaiti'
ELSE 'NOT KNG'
END AS "KWT_NKWT",
CASE
WHEN LENGTH(EMPLOYEE_ID) <=6 THEN 'KNG'
WHEN LENGTH(EMPLOYEE_ID)=12 THEN 'MOH'
ELSE 'Undefined'
END AS "KNG_MOH"
The issue is when I am filtering specific data using these 2 SQL scripts
--(1)
SELECT * FROM VIEW_USER_SETUP vus WHERE vus.KNG_MOH LIKE 'MOH'; --Issue
--(2)
SELECT * FROM VIEW_USER_SETUP vus WHERE vus.KWT_NKWT LIKE 'NOT KNG'; --Issue
The first issue the output is as follows:
SAP DBTech JDBC: [339]: invalid number: exception 71000339: SQL Error
The second issue the output is a follows:
invalid number: [6930] attribute value is not a number;exception 70006930: attribute value is not a number
To temporary solve 1, I use the below code:
SELECT * FROM VIEW_USER_SETUP vus WHERE vus.KNG_MOH NOT LIKE 'KNG';
Similarly to temporarily solve 2, I use the same above code because of the realtion.
I believe the issue is originating from the two CASE expressions created in the main view code, because when I use other filters from view there is no issue.
What is the correction required in the Main View code such that, when I execute --(1) and --(2), I get the required output?
Require help.