Not a valid month TO_DATE(inputMONYYYY, 'DD-MM-YYYY) - sql

Question

`I've to accept input as Month name and year and validate condition with date formatted as ‘DD-MM-YYY’.
This is my stored procedure:
create or replace PROCEDURE PROC_REPORT (
v_customer_id IN NUMBER,
v_user_id IN VARCHAR2 DEFAULT NULL,
monthYear IN VARCHAR2 DEFAULT NULL,
solutionType IN VARCHAR2 DEFAULT NULL,
customerAccNo IN VARCHAR2 DEFAULT NULL,
productType IN VARCHAR2 DEFAULT NULL,
output OUT SYS_REFCURSOR
) IS
BEGIN
DECLARE
selectclause CLOB;
whereclause CLOB;
startDate CLOB;
BEGIN
whereclause := ' where 1=1';
startDate := TO_CHAR(TO_DATE(monthYear,'MON YYYY', 'NLS_DATE_LANGUAGE = English'), 'DD-MM-YYYY');
IF monthYear IS NOT NULL THEN
whereclause := whereclause
|| ‘ and sm.activation_date >= ’
|| startDate;
END IF;
selectclause := 'select * from customer_master cm
inner join sim_master sm on sm.customer_id = cm.customer_id
inner join solution_type st on st.id_key = cm.solution_type ' || whereclause;
dbms_output.put_line(selectclause);
OPEN output FOR selectclause;
END;
END PROC_REPORT;
This gives error “not a valid month”. When I hard code monthYear as below, it works well:
startDate := TO_CHAR(TO_DATE('JAN 2023','MON YYYY', 'NLS_DATE_LANGUAGE = English'), 'DD-MM-YYYY');
I've tried converting monthYear to char as:
startDate := TO_CHAR(TO_DATE(TO_CHAR(monthYear),'MON YYYY', 'NLS_DATE_LANGUAGE = English'), 'DD-MM-YYYY');
Please help me understand what am I missing.`

Answer 1

You do not need dynamic SQL and can use OR in the WHERE clause:
create or replace PROCEDURE PROC_REPORT (
v_customer_id IN NUMBER,
v_user_id IN VARCHAR2 DEFAULT NULL,
monthYear IN VARCHAR2 DEFAULT NULL,
solutionType IN VARCHAR2 DEFAULT NULL,
customerAccNo IN VARCHAR2 DEFAULT NULL,
productType IN VARCHAR2 DEFAULT NULL,
output OUT SYS_REFCURSOR
)
IS
BEGIN
OPEN output FOR
SELECT *
FROM customer_master cm
inner join sim_master sm on sm.customer_id = cm.customer_id
inner join solution_type st on st.id_key = cm.solution_type
WHERE ( monthYear IS NULL
OR sm.activation_date >= TO_DATE(monthYear,'MON YYYY', 'NLS_DATE_LANGUAGE = English')
);
END PROC_REPORT;
/
I assume that activation_date is a DATE column; in which case you want to perform the comparison as DATEs (and not as formatted strings, so you do not want to convert back to a string).