SQL & PL/SQL

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SQL> declare
  2     ignore_column_name varchar2 (100) := 'ENAME';
  3     CURSOR C1 is
  4     SELECT column_name
  5     FROM user_tab_columns
  6     WHERE table_name = 'EMP'
  7  --   AND column_name NOT IN (ignore_column_name)
  8  ;
  9  begin
 10     for r in c1
 11     loop
 12        dbms_output.put_line ('result: '||r.column_name);
 13     end loop;
 14  end;
 15  /
result: EMPNO
result: ENAME
result: JOB
result: MGR
result: HIREDATE
result: SAL
result: COMM
result: DEPTNO

PL/SQL procedure successfully completed.

SQL> 
SQL> 
SQL> declare
  2     ignore_column_name varchar2 (100) := 'ENAME';
  3     CURSOR C1 is
  4     SELECT column_name
  5     FROM user_tab_columns
  6     WHERE table_name = 'EMP'
  7     AND column_name NOT IN (ignore_column_name)
  8  ;
  9  begin
 10     for r in c1
 11     loop
 12        dbms_output.put_line ('result: '||r.column_name);
 13     end loop;
 14  end;
 15  /
result: EMPNO
result: JOB
result: MGR
result: HIREDATE
result: SAL
result: COMM
result: DEPTNO

PL/SQL procedure successfully completed.

SQL> 

Hello,

the only difference between your program and mine is that..

ignore_column_name variable is declared but not initialized before the cursor. I mean..

declare
ignore_columns_name varchar2(100);
cursor c1 is
select column_name
from user_tab_columns
where column_name not in (ignore_column_name);
begin
ignore_column_name := 'LNAME';
for r in c1
loop
column := column||','||r.column_name;
end loop;
##REST OF THE CODE##
end;
/

the thing is .. ignore_column_name is not hardcoded, instead it is generated from a different part of the code. so I cannot initialise it like u have shown it. Can u help me? is it possible to achieve this?

Thanks

It doesn't make a difference if it's initialized before the cursor declaration or not, just as long as it's initialized before the cursor is opened.

SQL> declare
  2    ignore_column_name varchar2 (100);
  3    CURSOR C1 is
  4    SELECT column_name
  5    FROM user_tab_columns
  6    WHERE table_name = 'EMP'
  7    AND column_name NOT IN (ignore_column_name);
  8  begin
  9    ignore_column_name := 'ENAME';
 10    for r in c1
 11    loop
 12       dbms_output.put_line ('result: '||r.column_name);
 13    end loop;
 14  end;
 15  /
result: EMPNO
result: JOB
result: MGR
result: HIREDATE
result: SAL
result: COMM
result: DEPTNO

PL/SQL procedure successfully completed.

SQL>

Hello,

This was a really helpful reply.. it cleared my only suspicion but not my problem. Here I am pasting the entire code.. I will highlight the part thats not working.. Please let me know what you think the problem is.

CREATE OR REPLACE PROCEDURE
test_etl1
(
table1 IN user_tab_columns.table_name%TYPE,
table2 IN user_tab_columns.table_name%TYPE
) IS
col_list VARCHAR2(3000);
new_col_list VARCHAR2(3000);
column_name VARCHAR2(100);
num number;
table3 VARCHAR2(100);
column_list VARCHAR2(3000);
stmt VARCHAR2(3000);
CURSOR C1 IS
SELECT column_list
FROM ignore_columns
WHERE table_name = table1;
CURSOR C2 IS
SELECT column_name
FROM user_tab_columns
WHERE table_name = table3
AND column_name NOT IN (new_col_list);
BEGIN
col_list := null;
FOR R1 in C1
LOOP
col_list := R1.column_list;
END LOOP;
num := length(col_list);

WHILE num <> 1
LOOP
column_name := SUBSTR(col_list, 0,INSTR(col_list,' '));

IF (NVL(SUBSTR(col_list, INSTR(col_list, ' '), LENGTH(col_list)),'1') != '1')
THEN
col_list := SUBSTR(col_list, INSTR(col_list, ' '), LENGTH(col_list));
col_list := LTRIM(col_list);
new_col_list := new_col_list||''''||RTRIM(column_name)||''''||',';
ELSE
num := 1;
END IF;
END LOOP;

new_col_list := RTRIM(new_col_list,',');

table3 := upper(table1);
FOR R2 IN C2
LOOP
* column_list := column_list||''''||R2.column_name||''''||',';*
END LOOP;
column_list := RTRIM(column_list,',');
stmt := 'CREATE TABLE error_table AS SELECT '||column_list||' FROM '||table1||' MINUS SELECT '||column_list||'FROM '||table2;

END;

Table ignore_columns contains a single row.
table_name = patient_v
column_list = 'LAST_NAME'; with the quotes

Thanks