PL/SQL Using CASE in WHERE clause - plsql

Question

Good day Stackoverflow!
I have a query that is giving me an error: "Missing Right Parenthesis", at least, so says SQL Developer.
My query has a CASE statement within the WHERE clause that takes a parameter, and then executing a condition based on the value entered.
I've read that when using a CASE statement within a WHERE clause you have to surround the statement with parenthesis and assign it to a numeric value, e.g. "1", however doing so does not accomplish my goal.
My goal is to execute a condition in the CASE statement if that condition is met.
Would you mind taking a look and giving me some input please?
Thanks!
SELECT ...
FROM ....
WHERE 1 = 1
AND (
CASE :P_REPORT_PERIOD
WHEN 'SPRING'
THEN ((fiscal_year = (EXTRACT(YEAR FROM (SYSDATE))-1) AND period >=10) OR (fiscal_year = (EXTRACT(YEAR FROM (SYSDATE))) AND period < 4))
WHEN 'FALL'
THEN ((fiscal_year = (EXTRACT(YEAR FROM (SYSDATE))) AND period >=4) OR (fiscal_year = (EXTRACT(YEAR FROM (SYSDATE))) AND period < 10))
END
) = 1

Answer 1

Problem Solved, THANKS to all those that attempted finding a solution.
Solution: Rather than using a CASE statement, I just created a stored procedure, replaced the CASE with IF and built a VSQL string from my query.
Example:
VSQL := 'SELECT.....'
IF (v_rpt_pd = 'SPRING') THEN
VSQL := VSQL || '( ( AND EXTRACT(YEAR FROM (SYSDATE))-1 = fiscal_year and period >=10) or ';
VSQL := VSQL || ' ( AND EXTRACT(YEAR FROM (SYSDATE)) = fiscal_year and period <=3) )';
ELSE
VSQL := VSQL || '( ( AND EXTRACT(YEAR FROM (SYSDATE)) = fiscal_year and period >=4) or ';
VSQL := VSQL || ' ( AND EXTRACT(YEAR FROM (SYSDATE)) = fiscal_year and period <=9) )';
END IF;
VSQL := VSQL ||' GROUP BY fiscal_year, period
and so on, if you want the entire solution, DM me and I'll send you the code.
Cheers!

Answer 2

As per Tom the CASE syntax in WHERE CLAUSE is -
--Syntax
select * from <table name>
where 1=1
and
(case
when <BOOLEAN_EXPRESSION>
then <SCALAR_RETURN_VALUE>
...
ELSE <SCALAR_RETURN_VALUE>
end) = <SCALAR_VALUE> ;
Example:
--Query
WITH SAMPLE_DATA AS
(select 100 COL1,999 COL2 from DUAL UNION ALL
select 200 COL1,888 COL2 from DUAL
)
SELECT * FROM SAMPLE_DATA
WHERE 1=1
AND (
CASE COL2
WHEN 999 THEN 1
ELSE 0
END
) = 1 ;
-- Output:
100 999