Order by in subquery (for jQuery jTable) doesn't work? - sql

Question

Some background:
My framework jQuery jTable, allows me to do pagination and sort columns, in my select query I need to retrieve n rows (from nth, to nth) and previously order the data by the selected column.
I have a table with n columns where would not exist some rows (this is an example):
To achieve the first requirement I wrote the follow procedure:
create or replace
PROCEDURE PR_SHOWVALUESOLD
(
PRMROWMIN IN NUMBER
, PRMROWMAX IN NUMBER
, CURSORRESULT OUT SYS_REFCURSOR
) AS
BEGIN
open CURSORRESULT for
select * from
(select v.*, rownum r,
(
select count(*) TOTALITEMS from TABLE1 v
) TOTALITEMS
from TABLE1 v
) d
where d.r >= PRMROWMIN and d.r <= PRMROWMAX;
END PR_SHOWVALUESOLD;
This work successfully, I execute the procedure with the follows parameters (PRMROWMIN = 6, PRMROWMAX = 9), the result of the procedure are in Output Varibles window.
Now comes the next step, I need to order the data before take from n to x row.
I rewrite the procedure to do this, but doesn't work:
CREATE OR REPLACE PROCEDURE PR_SHOWVALUES
(
PRMROWMIN IN NUMBER
, PRMROWMAX IN NUMBER
, PRMORDERCOL IN VARCHAR2
, PRMORDERDIR IN VARCHAR2
, CURSORRESULT OUT SYS_REFCURSOR
) AS
BEGIN
open CURSORRESULT for
select * from
(select v.*, rownum r,
(
select count(*) TOTALITEMS from TABLE1 v
) TOTALITEMS
from TABLE1 v
order by 'LOWER(' || PRMORDERCOL || ')' || ' ' || PRMORDERDIR
) d
where d.r >= PRMROWMIN and d.r <= PRMROWMAX;
END PR_SHOWVALUES;
I executed the modified procedure with the follows parameters:
PRMROWMIN := 6;
PRMROWMAX := 9;
PRMORDERCOL := 'COLUMNA';
PRMORDERDIR := 'DESC';
I expected the highlighted rows Query Result 2 window (but this new procedure retrieve the same data as old but disordered Output Variables Window):
How to achieve my requirements?
Thanks in advance.

Answer 1

This is your order by:
order by 'LOWER(' || PRMORDERCOL || ')' || ' ' || PRMORDERDIR
It is not applying the function lower(). Instead, it is concatenating the strings. You may mean:
order by LOWER(PRMORDERCOL) ' ' || PRMORDERDIR

Answer 2

I found a solution to my requirement.
I need to use DECODE to match every column to sort.
I can order in subquery, in this case I do two order by in two subqueries.
The documentation of PL/SQL DECODE function are in:
PL/SQL DECODE FUNCTION
The final Procedure are:
CREATE OR REPLACE PROCEDURE PR_SHOWVALUES
(
PRMROWMIN IN NUMBER
, PRMROWMAX IN NUMBER
, PRMORDERCOL IN VARCHAR2
, PRMORDERDIR IN VARCHAR2
, CURSORRESULT OUT SYS_REFCURSOR
) AS
BEGIN
open CURSORRESULT for
select * from (
select rownum r, v.* from
(
select * from
(
select * from table1 tbl
order by decode
(
UPPER(PRMORDERCOL),
'COLUMNA', LOWER(tbl.COLUMNA),
'COLUMNB', LOWER(tbl.COLUMNB),
LOWER(tbl.TABLE1_ID)
)
)
ORDER BY
CASE
WHEN UPPER(PRMORDERDIR) = 'DESC' THEN
ROWNUM * -1
ELSE
ROWNUM
END
) v
)
where r >= PRMROWMIN and r <= PRMROWMAX;
END PR_SHOWVALUES;
Acknowledgment to Jack David Baucum where I found the solution.