Oracle 10g simple query error - plsql

Question

Oracle SQL Developer complains about next SQL though I can't seem to find the reason:
IF to_number(to_char(sysdate, 'HH24')) > 6 THEN
IF to_number(to_char(sysdate, 'HH24')) < 9 THEN
SELECT 1 FROM dual;
ELSE
SELECT (CASE WHEN result = 'SUCCESS' THEN 1 ELSE 0 END) FROM t_job WHERE to_char(start_time, 'yyyy/mm/dd') = to_char(sysdate, 'yyyy/mm/dd');
END IF;
ELSE
SELECT (CASE WHEN result = 'SUCCESS' THEN 1 ELSE 0 END) FROM t_job WHERE to_char(start_time, 'yyyy/mm/dd') = to_char(sysdate, 'yyyy/mm/dd');
END IF;
What's the mistake in provided query?
Error report:
Error starting at line 7 in command:
ELSE
Error report:
Unknown Command
(CASEWHENRESULT='SUCCESS'THEN1ELSE0END)
---------------------------------------
1
Error starting at line 9 in command:
END IF
Error report:
Unknown Command

Answer 1

There are a couple of problems with your code (which is PL/SQL, not just SQL):
1) You are missing the begin and end around the block.
2) Your selects need an into clause
try:
DECLARE
l_result number;
BEGIN
IF to_number(to_char(sysdate, 'HH24')) > 6 THEN
IF to_number(to_char(sysdate, 'HH24')) < 9 THEN
SELECT 1 INTO l_result FROM dual;
ELSE
SELECT (CASE WHEN result = 'SUCCESS' THEN 1 ELSE 0 END)
INTO l_result
FROM t_job WHERE to_char(start_time, 'yyyy/mm/dd') = to_char(sysdate, 'yyyy/mm/dd');
END IF;
ELSE
SELECT (CASE WHEN result = 'SUCCESS' THEN 1 ELSE 0 END)
INTO l_result
FROM t_job WHERE to_char(start_time, 'yyyy/mm/dd') = to_char(sysdate, 'yyyy/mm/dd');
END IF;
dbms_output.put_line('result is '||l_result);
END;

Answer 2

Since this is a PL/SQL block, your SELECT statements would need to select the data into some local variable or they would need to be used in a cursor. Which approach you want would depend on how many rows in T_JOB could potentially match the criteria you're specifying. Assuming all three statements would return exactly 1 row, you could do something like this (code simplified to avoid repeating the same query twice)
DECLARE
l_some_local_variable PLS_INTEGER;
BEGIN
IF( to_number( to_char( sysdate, 'HH24' ) ) > 6 and
to_number( to_char( sysdate, 'HH24' ) ) < 9 )
THEN
SELECT 1
INTO l_some_local_variable
FROM dual;
ELSE
SELECT (CASE WHEN result = 'SUCCESS'
THEN 1
ELSE 0
END)
INTO l_some_local_variable
FROM t_job
WHERE trunc( start_time ) = trunc( sysdate );
END IF;
END;
Of course, once you populate the data in your local variable, you would need to actually do something with the value. Potentially, you may want to create a function that returns the local variable rather than using an anonymous PL/SQL block as I have done here.