I have the following table TEMP
I want to create a pivot view using SQL, Ordered by CATEGORY
ASC ,by LEVEL
DESC and S
A stored function(or procedure) might be created in order to create a SQL for Dynamic Pivoting, and the result set is loaded into a variable of type SYS_REFCURSOR
:
CREATE OR REPLACE FUNCTION Get_Categories_RS RETURN SYS_REFCURSOR IS
v_recordset SYS_REFCURSOR;
v_sql VARCHAR2(32767);
v_cols_1 VARCHAR2(32767);
v_cols_2 VARCHAR2(32767);
BEGIN
SELECT LISTAGG( ''''||"level"||''' AS "'||"level"||'"' , ',' )
WITHIN GROUP ( ORDER BY "level" DESC )
INTO v_cols_1
FROM (
SELECT DISTINCT "level"
FROM temp
);
SELECT LISTAGG( 'MAX(CASE WHEN category = '''||category||''' THEN "'||"level"||'" END) AS "'||"level"||'_'||category||'"' , ',' )
WITHIN GROUP ( ORDER BY category, "level" DESC )
INTO v_cols_2
FROM (
SELECT DISTINCT "level", category
FROM temp
);
v_sql :=
'SELECT "set", '|| v_cols_2 ||'
FROM
(
SELECT *
FROM temp
PIVOT
(
MAX(value) FOR "level" IN ( '|| v_cols_1 ||' )
)
)
GROUP BY "set"
ORDER BY "set"';
OPEN v_recordset FOR v_sql;
RETURN v_recordset;
END;
in which I used two levels of pivoting : the first is within the inner query involving PIVOT
Clause, and the second is in the outer query having the conditional aggregation logic. Notice that the order of levels should be in the descending order( Z
, Y
, X
) within the expected result as conforming to the description.
And then invoke
VAR rc REFCURSOR
EXEC :rc := Get_Categories_RS;
PRINT rc
from SQL Developer's Command Line in order to get the result set
Btw, avoid using reserved keywords such as set
and level
as in your case. I needed to quote them in order to be able to use.