My workflow follows: I developed some SQL statements according to a certain logic. Then I am asked to bundle the SQL statement into PL/SQL block to help trigger/schedule the execution of said statements.
At that point, I can see that PL/SQL block (despite being copy/paste of the SQL statement + passing argument) does not give the same results.
While I can DBMS_OUTPUT.PUT_LINE the arguments to check they are what was intended, I did not find a way to peek into what happens in the WITH clause of the SELECT statement.
I tried SELECT INTO a local variable of the PL/SQL block, but it is not allowed to do SELECT INTO if not at the outer-most SELECT (which is never going to be the case in an element of a WITH clause).
So the question is how to troubleshoot this type of statement?
I don’t have an MRE, I am looking for a general solution to change my workflow rather than a workaround for this case.
Note: I am fine with a high-level answer so long I could practically use it. (for instance: "never use WITH clause in PL/SQL" would be fine).
Note: I say "troubleshoot", because I can’t debug as the DBA didn’t grant debug rights, and ETA to get debug rights granted is more than 12 months away.
>Solution :
If you want to see what is going on with a WITH clause such as:
WITH sqfc1 (a, b, c, d, e) AS (
SELECT a, b, c, d, e
FROM table_name
WHERE f = 'something'
),
sqfc2 (a, b, c, d, m) AS (
SELECT a, b, c, d, 2 * e + d
FROM sqfc1
WHERE a > 0 OR b > 0
)
SELECT a, d, m, b + c AS n
FROM sqfc2
WHERE m > 3 AND d > 0;
and you want to see what is going on in the first sub-query factoring clause then just repeat the SQL statement and stop after the first clause:
WITH sqfc1 (a, b, c, d, e) AS (
SELECT a, b, c, d, e
FROM table_name
WHERE f = 'something'
)
SELECT *
FROM sqfc1
And you will see what is going on.
Then I am asked to bundle the SQL statement into PL/SQL block … how to troubleshoot this type of statement?
Do exactly the same thing but wrap it in a cursor or use BULK COLLECT INTO and then loop through the cursor or collection and print the rows with DBMS_OUTPUT.
BEGIN
FOR r IN (
WITH sqfc1 (a, b, c, d, e) AS (
SELECT a, b, c, d, e
FROM table_name
WHERE f = 'something'
)
SELECT *
FROM sqfc1
) LOOP
DBMS_OUTPUT.PUT_LINE(r.a || ', ' || r.b || ', ' || r.c || ', ' || r.d || ', ' || r.e);
END LOOP;
END;
/
db<>fiddle here