Nested CASE statement in UPDATE SET clause - sql

Question

I am attempting to switch a value based on a set of conditions and I have noticed that where I have a nested CASE statement within the SET clause of my UPDATE expression, the columns are not updating.
When a simple CASE expression existis the columns appear to be updating. However, for the OVERRIDDEN_CHECK_NUMBER and OVERRIDDEN_AMOUNT in this example, the columns are not updating.
The OVERRIDDEN_DATE, OVERRIDDEN_USER_ID, CHECK_NO and AMOUNT columns in the UPDATE are updating without issue.
Can anyone tell me why the OVERRIDDEN_CHECK_NUMBER and OVERRIDDEN_AMOUNT will not update in this UPDATE statement?
Are nested CASE statements not tallowed in the SET clause of the UPDATE expression?
SQL EXAMPLE
UPDATE WAREHOUSE.BANK_STATEMENT_ACTIVITY
SET OVERRIDDEN_CHECK_NO = --(CASE :btn
(CASE WHEN (:btn = '1') THEN CASE WHEN '141973' = '141973' THEN NULL
WHEN '141973' != '999999' THEN LPAD(TRIM(141973), 12, '0')
END
WHEN (:btn = '2') THEN '1740 - Previously Paid Warrant'
ELSE NULL
END),
OVERRIDDEN_AMOUNT = --(CASE :btn
(CASE WHEN (:btn = '1') THEN CASE WHEN 253.20 = 253.20 THEN NULL
WHEN 253.20 != 999.99 THEN LPAD(TRIM(253.20), 12, '0')
END
WHEN (:btn = '2') THEN NULL
ELSE NULL
END),
OVERRIDDEN_DATE = SYSDATE,
OVERRIDDEN_USER_ID = 1009,
CHECK_NO = (CASE :btn
WHEN '1' THEN LPAD(TRIM(999999), 12, '0')
WHEN '2' THEN '142775'
ELSE NULL
END),
AMOUNT = (CASE :btn
WHEN '1' THEN TRIM(78.60)
WHEN '2' THEN TRIM(253.20)
ELSE NULL
END)
WHERE TO_NUMBER(CHECK_NO) = (CASE :btn
WHEN '1' THEN '141973'
WHEN '2' THEN '142775'
ELSE NULL
END)
AND AMOUNT = (CASE :btn
WHEN '1' THEN 78.60
WHEN '2' THEN 253.20
ELSE NULL
END)
AND TRUNC(LOAD_DATE) = (CASE :btn
WHEN '1' THEN TRUNC(LOAD_DATE)
WHEN '2' THEN (SELECT (MAX(LOAD_DATE)) FROM WAREHOUSE.BANK_STATEMENT_ACTIVITY)
ELSE NULL
END)
AND BANKACCTNO = (SELECT LONGDESC
FROM TCMS.COMPLEMENTARY_VALIDATIONS
WHERE TEXTCODE = 'BANKACCT'
AND CODE = 80);
EDIT
After fixing the logival issue that #mathguy pointed out the update query via the editor worked. However, when executing this via the PL/SQL pacakge the table update fails.
Here is the before update:
Before - result
Her is the after result:
After - result
They are identical.
This is the actual package procedure:
PROCEDURE UpdateBankStatementActivity( btn IN VARCHAR2)
AS
BEGIN
DBMS_OUTPUT.PUT_LINE( 'UpdateBankStatementActivity - btn: ' || btn );
DBMS_OUTPUT.PUT_LINE( 'UpdateBankStatementActivity - bsa_rec.OVERRIDDEN_CHECK_NO: ' || bsa_rec.OVERRIDDEN_CHECK_NO || CHR(10) ||
'bsa_rec.OVERRIDDEN_AMOUNT: ' || bsa_rec.OVERRIDDEN_AMOUNT || CHR(10) ||
'bsa_rec.CHECK_NO: ' || bsa_rec.CHECK_NO || CHR(10) ||
'bsa_rec.AMOUNT: ' || bsa_rec.AMOUNT || CHR(10) ||
'bsa_rec.LOAD_DATE:' || bsa_rec.LOAD_DATE );
UPDATE WAREHOUSE.BANK_STATEMENT_ACTIVITY
SET OVERRIDDEN_CHECK_NO = --(CASE :btn
(CASE WHEN (btn = '1') THEN CASE WHEN bsa_rec.OVERRIDDEN_CHECK_NO = bsa_rec.CHECK_NO THEN NULL
WHEN bsa_rec.OVERRIDDEN_CHECK_NO != bsa_rec.CHECK_NO THEN LPAD(TRIM(bsa_rec.OVERRIDDEN_CHECK_NO), 12, '0')
END
WHEN (btn = '2') THEN '1740 - Previously Paid Warrant'
ELSE NULL
END),
OVERRIDDEN_AMOUNT = --(CASE :btn
(CASE WHEN (btn = '1') THEN CASE WHEN bsa_rec.OVERRIDDEN_AMOUNT = bsa_rec.AMOUNT THEN NULL
WHEN bsa_rec.OVERRIDDEN_AMOUNT != bsa_rec.AMOUNT THEN LPAD(TRIM(bsa_rec.OVERRIDDEN_AMOUNT), 12, '0')
END
WHEN (btn = '2') THEN NULL
ELSE NULL
END),
OVERRIDDEN_DATE = SYSDATE,
OVERRIDDEN_USER_ID = bsa_rec.OVERRIDDEN_USER_ID,
CHECK_NO = (CASE btn
WHEN '1' THEN LPAD(TRIM(bsa_rec.CHECK_NO), 12, '0')
WHEN '2' THEN LPAD(TRIM(bsa_rec.CHECK_NO), 12, '0')
ELSE NULL
END),
AMOUNT = (CASE btn
WHEN '1' THEN TRIM(bsa_rec.OVERRIDDEN_AMOUNT)
WHEN '2' THEN TRIM(bsa_rec.AMOUNT)
ELSE NULL
END)
WHERE TO_NUMBER(CHECK_NO) = (CASE btn
WHEN '1' THEN bsa_rec.OVERRIDDEN_CHECK_NO
WHEN '2' THEN bsa_rec.CHECK_NO
ELSE NULL
END)
AND AMOUNT = (CASE btn
WHEN '1' THEN bsa_rec.OVERRIDDEN_AMOUNT
WHEN '2' THEN bsa_rec.AMOUNT
ELSE NULL
END)
AND TRUNC(LOAD_DATE) = (CASE btn
WHEN '1' THEN TRUNC(bsa_rec.LOAD_DATE)
WHEN '2' THEN (SELECT MAX(LOAD_DATE) FROM WAREHOUSE.BANK_STATEMENT_ACTIVITY)
ELSE NULL
END)
AND BANKACCTNO = (SELECT LONGDESC
FROM TCMS.COMPLEMENTARY_VALIDATIONS
WHERE TEXTCODE = 'BANKACCT'
AND CODE = 80);
COMMIT;
END UpdateBankStatementActivity;
The parameter values in the first SQL CODE snippet are consistent with the parameters in the PL/SQL block.

Answer 1

What do you mean by "not updating"?
There is a clear logical flaw in your nested case expressions, when :btn = '1'. Namely, the first branch of the "inner" case expression always evaluates to TRUE, so the "update value" will be null every time you pass in :btn = '1'. Is that the problem you are noticing? Then: For overridden_amount the result will always be null because of this; for overridden_check_no it will not be null if and only if :btn = '2'.
Note that you could write the "outer" case expressions with the same syntax you use for the simple expressions: case :btn when '1' then case .... end else ... end.
EDIT: Answering your modified question (perhaps). I am not sure I can follow the logic in its entirety; but what is happening in the example (assuming you called the procedure with btn = '1' is this:
Both the overridden_check_no and the overridden_amount are null in the original table. In the nested (inner) case expression for both columns you check two columns, with either = or !=. Neither of the tests is true when one of the terms is null! So the case evaluations falls through to the else clause, or when else is not included, to the default, which is null. The update actually did work, it just updated the values to null because none of the "actual branches" in the inner case statements evaluated to true.
You say, though, that this works OK if you just run it as a stand-alone SQL update, directly from your editor. I wonder how that is possible, unless - again - the code in the procedure is different from what you have in your editor.