Compile error oracle procedure - oracle

Question

Hej. I have a task that says to create a procedure that adds column "BRUTTO" to a table "TABELA_1, then fills that column with values based on values from column "NETTO" and output all records from TABLE_1, including newly created BRUTTO. It works without commented out code but doesn't otherwise. Apparently it doesn't see column BRUTTO yet so I can't reference it like that. Any help appreciated.
CREATE OR REPLACE PROCEDURE WSTAW_BRUTTO_I_WYSWIETL
AS
--CURSOR C IS
--SELECT NAZWISKO, NETTO, BRUTTO FROM TABELA_1;
V_VAT NUMBER(9,2) := 24;
BEGIN
EXECUTE IMMEDIATE 'ALTER TABLE TABELA_1 ADD BRUTTO NUMBER';
EXECUTE IMMEDIATE 'UPDATE TABELA_1 SET BRUTTO = NETTO * (1 + :1 /100)' USING V_VAT;
--FOR V_REC IN C
--LOOP
--DBMS_OUTPUT.PUT_LINE('| '||V_REC.NETTO||' | '||V_REC.BRUTTO);
--END LOOP;
END WSTAW_BRUTTO_I_WYSWIETL;

Answer 1

Your procedure won't compile because you can't access a column before it is added to the table. Not sure why you wrote a procedure with dynamic SQL for this. A plain SQL statement should work. Moreover, you can't use bind variable in a DDL, It would have raised
ORA-01027: bind variables not allowed for data definition operations
during run time.
You should also consider using BRUTTO as a VIRTUAL COLUMN, rather than a column itself.
ALTER TABLE TABELA_1 ADD BRUTTO NUMBER AS ( NETTO * (1 + 24 /100) );
Demo
If you still think you want a procedure and it has to compile, you should put the block inside EXECUTE IMMEDIATE, but it's not recommended.
CREATE OR REPLACE PROCEDURE wstaw_brutto_i_wyswietl AS
v_vat NUMBER(9,2) := 24;
BEGIN
EXECUTE IMMEDIATE 'ALTER TABLE TABELA_1 ADD BRUTTO NUMBER AS ( NETTO * (1 + '
|| v_vat
|| ' /100) )';
EXECUTE IMMEDIATE q'{BEGIN
FOR V_REC IN ( SELECT NETTO,BRUTTO FROM TABELA_1 )
LOOP
DBMS_OUTPUT.PUT_LINE(V_REC.NETTO||','||V_REC.BRUTTO);
END LOOP;
END;}'
;
END wstaw_brutto_i_wyswietl;
/
Demo2