Can anyone pls explain what this procedure does?

Question

i could only figure out that it will be performing a transpose.
create or replace
PROCEDURE TEST_TRANSPOSE(o_test OUT SYS_REFCURSOR) AS
report_exists number(3);
report_name varchar(30) := 'REPORT_TBL' ;
query_main varchar(16000) := 'create table ' || report_name || ' as select MAGAZINE ' ;
query_part varchar(1024) ;
my_var varchar2(5);
cursor cur_region is select distinct REGION from MAIN_TBL order by region;
begin
select count(*) into report_exists
from tab
where tname = report_name;
if ( report_exists = 1 ) then
execute immediate 'drop table ' || report_name ;
end if;
open cur_region ;
loop
fetch cur_region into my_var ;
exit when cur_region%NOTFOUND;
query_part := 'select nvl(sum(quantity),0) from MAIN_TBL x where x.magazine = main.magazine and x.region='''||my_var||'''' ;
query_main := query_main || chr(10) || ',(' || query_part || ')"' || my_var || '"';
end loop;
close cur_region ;
query_main := query_main || ' from (select distinct MAGAZINE from MAIN_TBL ) main' ;
DBMS_OUTPUT.PUT_LINE(query_main);
--execute immediate query_main ;
open o_test for query_main;
end;
{code}
i need to transpose  a table which has dynamic number of rows.This was what i tried.Could you pls bhelp me out to correct this i get "P_TRAN_YEAR" invalid identifier
[code]
create or replace
PROCEDURE         PRM_R_MAT_RPT (p_EmpID     IN  Integer,
P_TRAN_YEAR IN NUMBER,
P_TRAN_MONTH IN NUMBER,O_rc OUT sys_refcursor) IS
v_cnt NUMBER;
v_sql VARCHAR2(32767);
v_basic Number(16, 4);
BEGIN
select PPH_ORG_AMOUNT into v_basic from prm_p_hop
where pph_emp_id=p_empid
and pph_tran_year=p_tran_year
and pph_tran_month=P_TRAN_MONTH
and pph_hop_code=5
and PPH_SALARY_THRU='R';
-- SELECT  distinct count(*)
--  INTO v_cnt
--  FROM PRM_T_VAR_HOP
--  where PTVH_EMP_ID=p_EMPID
--  and PTVH_TRAN_YEAR=p_TRAN_YEAR
--  and PTVH_TRAN_MONTH=P_TRAN_MONTH;
v_sql := 'select  distinct PCH_SHORT_DESCRIPTION,v_basic,PTVH_AMOUNT Amount ';
--  FOR i IN 1..v_cnt
--  LOOP
v_sql := v_sql || ',max(decode(rn, PCH_SHORT_DESCRIPTION)) as description ';
--v_sql := v_sql || ',max(decode(rn, '||to_char(i)||', PDSL_INTEREST)) as interest'||to_char(i);
-- v_sql := v_sql || ',max(decode(rn, '||to_char(i)||', PDSL_PRINCIPAL_SALARY)) as principle'||to_char(i);
-- v_sql := v_sql || ',max(decode(rn, '||to_char(i)||', PDSL_SOCIETY_CODE)) as SOC_CODE'||to_char(i);
--  END LOOP;
v_sql := v_sql || ' from (select  PRM_T_VAR_HOP.*, PRM_C_HOP.*, row_number() over (partition by PTVH_EMP_ID order by PTVH_EMP_ID) as rn
from  
PRM_T_VAR_HOP,
PRM_C_HOP
WHERE PTVH_EMP_ID         =P_empid
And   PTVH_TRAN_YEAR      =P_TRAN_YEAR
And   PTVH_TRAN_MONTH     =P_TRAN_MONTH
And   PTVH_HOP_CODE       =PCH_HOP_CODE
AND   PCH_CALCULATION_BASIS=''V''
AND   PCH_TAG              =''C''
AND   PTVH_SALARY_THRU     =''R'')';
OPEN O_rc FOR v_sql;
END;
[/code]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Answer 1

Your first piece of code does not work, because a create table statement cannot be issued using a ref cursor like that. When executed with the "execute immediate" command, it works. Then, the refcursor is only a "select * from report_tbl".
What it does, is dynamically dropping and creating a table report_tbl and filling it with the results of a horribly inefficient pivot query. If the report_tbl has no other purpose after running this procedure, then I'd suggest to not drop and create tables dynamically like that. In the second variant of test_transpose, you can see how you can do that.
SQL> create table main_tbl (magazine,region,quantity)
  2  as
  3  select 'MAGAZINE1','REGION1',1 from dual union all
  4  select 'MAGAZINE1','REGION2',2 from dual union all
  5  select 'MAGAZINE1','REGION3',3 from dual union all
  6  select 'MAGAZINE2','REGION1',4 from dual union all
  7  select 'MAGAZINE2','REGION2',5 from dual union all
  8  select 'MAGAZINE2','REGION3',6 from dual
  9  /
Tabel is aangemaakt.
SQL> create or replace PROCEDURE TEST_TRANSPOSE(o_test OUT SYS_REFCURSOR)
  2  AS
  3    report_exists number(3);
  4    report_name varchar(30) := 'REPORT_TBL' ;
  5    query_main varchar(16000) := 'create table ' || report_name || ' as select MAGAZINE ' ;
  6    query_part varchar(1024) ;
  7    my_var varchar2(7);
  8
  9    cursor cur_region is select distinct REGION from MAIN_TBL order by region;
10  begin
11    select count(*) into report_exists
12    from tab
13    where tname = report_name;
14    if ( report_exists = 1 ) then
15    execute immediate 'drop table ' || report_name ;
16    end if;
17
18    open cur_region ;
19    loop
20      fetch cur_region into my_var ;
21      exit when cur_region%NOTFOUND;
22      query_part := 'select nvl(sum(quantity),0) from MAIN_TBL x where x.magazine = main.magazine and x.region='''||my_var||'''' ;
23      query_main := query_main || chr(10) || ',(' || query_part || ')"' || my_var || '"';
24    end loop;
25    close cur_region ;
26
27    query_main := query_main || ' from (select distinct MAGAZINE from MAIN_TBL ) main' ;
28    execute immediate query_main;
29    open o_test for 'select * from ' || report_name;
30  end;
31  /
Procedure is aangemaakt.
SQL> var rc refcursor
SQL> exec test_transpose(:rc)
PL/SQL-procedure is geslaagd.
SQL> print rc
MAGAZINE     REGION1    REGION2    REGION3
MAGAZINE1          1          2          3
MAGAZINE2          4          5          6
2 rijen zijn geselecteerd.
SQL> create or replace procedure test_transpose (o_test out sys_refcursor)
  2  as
  3    l_query varchar2(1000) := 'select magazine';
  4  begin
  5    for r in (select distinct region from main_tbl)
  6    loop
  7      l_query := l_query || ', sum(decode(region,''' || r.region || ''',quantity)) ' || r.region;
  8    end loop;
  9    l_query := l_query || ' from main_tbl group by magazine';
10    open o_test for l_query;
11  end;
12  /
Procedure is aangemaakt.
SQL> exec test_transpose(:rc)
PL/SQL-procedure is geslaagd.
SQL> print rc
MAGAZINE     REGION1    REGION2    REGION3
MAGAZINE1          1          2          3
MAGAZINE2          4          5          6
2 rijen zijn geselecteerd.Regards,
Rob.