Pagination in Oracle/PLSQL error - oracle

Question

Hey I am trying to add paging to my dynamic sql block in PLSQL but for some reason when I run the test script it errors out:
ORA-00932: inconsistent datatypes: expected - got -
Here is my procedure:
create or replace
procedure spm_search_patientmedrecs (
p_columnsort_in in varchar2,
p_column1_in in varchar2,
p_column2_in in varchar2,
p_column3_in in varchar2,
p_column4_in in varchar2,
p_ascdesc_in in varchar2,
p_return_cur_out out sys_refcursor
is
lv_sql varchar2(32767);
lv_startnum number:= 1;
lv_incrementby number:= 20;
begin
lv_sql := '';
lv_sql := 'select * from (
select /*+ first_rows(20) */
'||p_column1_in||',
'||p_column2_in||',
'||p_column3_in||',
'||p_column4_in||',
row_number() over
(order by '||p_columnsort_in||' '||p_ascdesc_in||') rn
from membermedicalreconcilationhdr h,
membermedicalreconcilationdet d
where h.membermedreconciliationhdrskey =
d.membermedreconciliationhdrskey)
where rn between :lv_startnum and :lv_incrementby
order by rn';
open p_return_cur_out for lv_sql;
end spm_search_patientmedrecs;
Here is my test script:
set serveroutput on
declare
type tempcursor is ref cursor;
v_cur_result tempcursor;
p_columnsort_in varchar2(50);
p_column1_in varchar2(50);
p_column2_in varchar2(50);
p_column3_in varchar2(50);
p_column4_in varchar2(50);
p_ascdesc_in varchar2(50);
begin
spm_search_patientmedrecs
('h.PRIMARYMEMBERPLANID',
'h.PRIMARYMEMBERPLANID',
'h.ASSIGNEDUSERID',
'd.MEMBERMEDRECONCILIATIONDETSKEY',
'd.GENERICNM',
'ASC',
v_cur_result
);
loop
fetch v_cur_result into
p_column1_in,p_column2_in,p_column3_in,p_column4_in;
dbms_output.put_line('column 1: '||p_column1_in||' column 2: '||p_column2_in||
' column 3: '||p_column3_in||' column 4: '||p_column4_in);
exit when v_cur_result%notfound;
end loop;
end;
The error I posted above doesnt make sense to me, but I've been looking for the cause for awhile. If anyone can point me in the right direction it would be much appreciated, thanks in advance.

Answer 1

A couple of issues jump out at me.
The query that you are using to return the cursor returns 5 columns (the 4 you pass in plus the computed rn) while your fetch fetches the data into only 4 variables. You would either need to modify your query to return only 4 columns or modify your test script to fetch the data into 5 variables.
In your procedure, you have bind variables in your SQL statement but you don't pass in any bind variables when you open the cursor. My guess is that you want something like this
Passing the bind variables with the USING clause
open p_return_cur_out
for lv_sql
using lv_startnum, lv_incrementby;
There may well be more errors-- if there are, it would be helpful to post the full stack trace including the line number of the error.
A couple of other things to be aware of.
Unless p_columnsort_in happens to specify a column that is unique, your paging code may well miss rows and/or show rows in multiple pages because the sort order isn't fully specified. If rows 20 and 21 have the same p_columnsort_in value, it would be perfectly legal to sort them one way on the first query and another way on the second query so row 20 might show up on the first and second page and row 21 might not show up anywhere.
If efficiency is a concern, using rownum will probably end up being more efficient than using the analytic function like this because the optimizer can generally do a better job of optimizing a rownum predicate.

Answer 2

create or replace
procedure spm_search_patientmedrecs (
p_columnsort_in in varchar2,
p_column1_in in varchar2,
p_column2_in in varchar2,
p_column3_in in varchar2,
p_column4_in in varchar2,
p_ascdesc_in in varchar2,
p_return_cur_out out sys_refcursor
is
lv_sql varchar2(32767);
lv_startnum number:= 1;
lv_incrementby number:= 20;
begin
lv_sql := 'select * from (
select /*+ first_rows(20) */
'||p_column1_in||',
'||p_column2_in||',
'||p_column3_in||',
'||p_column4_in||',
row_number() over
(order by '||p_columnsort_in||' '||p_ascdesc_in||') rn
from membermedicalreconcilationhdr h,
membermedicalreconcilationdet d
where h.membermedreconciliationhdrskey =
d.membermedreconciliationhdrskey)
where rn between :1 and :2
order by rn';
open p_return_cur_out for lv_sql using lv_startnum, lv_incrementby;
end spm_search_patientmedrecs;