Fetching data from a nested table into cursor

Requirement

The table XYZ contains the column p_type which contains the column name of PQR table . Now here I am fetching a record from the XYZ table and sum(amount) on the basis of the group by p_type which is fetched from the record from table XYZ. I have used partition by because I also want t_id and not in group by. Now I take the records fetched from PQR table and compare with a record of the XYZ table, and for each record fetched from PQR table, sum(amount) is compared with a record of XYZ table.

Question

I have fetched the xyz_id and t_id in the nested table, but I want to take this in cursor, IS there any way to do this so that I can select these record in one go.

The probable solution I found is to take a temporary table, but if I dont want to use a temp table, then what will be the solution.

DECLARE

type queryCursor is ref cursor;
v_ref queryCursor;

v_query queryCursor;
v_t_id   pqr.t_id%TYPE;
v_total         NUMBER (38);

CURSOR varcursor
IS
SELECT abc_id,p_type,p_amount
    FROM xyz;

v_temp          VARCHAR2 (4000);
v_temp1         VARCHAR2 (200);
v_temp2         VARCHAR2 (200);

TYPE XYZ_table IS TABLE OF  XYZ%ROWTYPE;
v_XYZ XYZ_table :=XYZ_table();
TYPE PQR_table IS TABLE OF PQR%ROWTYPE;
v_PQR PQR_table :=XYZ_table();
BEGIN

FOR varcursor_rec IN varcursor
LOOP
v_temp1 := varcursor_rec.p_type; --p_type contains column name of the pqr table
v_temp :=
        'SELECT T_ID,SUM(AMOUNT) OVER (PARTITION BY '
     || v_temp1
     || ' ORDER BY '
     || v_temp1
     || ') total from pqr
     ||';
 
 OPEN v_ref FOR v_temp;
  LOOP
FETCH V_REF into v_t_id,v_total;
exit when V_REF%notfound;
IF varcursor_rec.p_amount <v_total
THEN
counter:=counter+1;
v_XYZ.EXTEND;
v_PQR.EXTEND;
v_XYZ(counter).xyz_id:=varcursor_rec.xyz_id;
v_PQR(counter).t_id:=varcursor_rec.t_id;
      
 --HOW CAN I FETCH THE 
      
END IF;
END LOOP;
END LOOP;
END;
/

XYZ Table:

xyz_id                p_type          p_amount
============================================================
p_1                 p_id                 100000
p_2             p_id,t_status            100    

PQR Table:

T_id            p_id    amount    t_status
=================================================
1               E1      100       open
2               E2      开发者_如何学Go200       open
3               E1      200       close
4               E2      300       open
5               E1      100       close

You can do this by using declared object types and tables of declared object types.

Let's start by creating the tables and data:

CREATE TABLE xyz
( xyz_id VARCHAR2(3)
, p_type VARCHAR2(20)
, p_amount NUMBER
);

INSERT INTO xyz VALUES ('p_1','p_id','100000');
INSERT INTO xyz VALUES ('p_2','p_id,t_status','100');

CREATE TABLE pqr
( t_id NUMBER
, p_id VARCHAR2(2)
, amount NUMBER
, t_status VARCHAR2(5)
);

INSERT INTO pqr VALUES (1,'E1',100,'open');
INSERT INTO pqr VALUES (2,'E2',200,'open');
INSERT INTO pqr VALUES (3,'E1',200,'close');
INSERT INTO pqr VALUES (4,'E2',300,'open');
INSERT INTO pqr VALUES (5,'E1',100,'close');

Next, create the declared object types:

CREATE TYPE pqr_tid_sumamt_rec IS OBJECT
( t_id NUMBER
, sum_amount NUMBER
);

CREATE TYPE pqr_tid_sumamt_tab IS TABLE OF pqr_tid_sumamt_rec;

CREATE TYPE xyztab_ptstab_rec IS OBJECT
( xyz_id VARCHAR2(3)
, p_type VARCHAR2(20)
, p_amount NUMBER
, p_pqr_tid_sumamt_tab pqr_tid_sumamt_tab
);

CREATE TYPE xyztab_ptstab_tab AS TABLE OF xyztab_ptstab_rec;

Now, we'll create the function that will return a sys_refcursor with a nested table:

CREATE OR REPLACE
FUNCTION xyz_pqr_refcursor 
    RETURN sys_refcursor
IS
    TYPE querycursor IS REF CURSOR;
    v_ref querycursor;
    v_query querycursor;
    v_t_id   pqr.t_id%TYPE;
    v_total         NUMBER (38);
    CURSOR varcursor IS 
        SELECT xyz_id,p_type,p_amount    
        FROM xyz;
    v_temp          VARCHAR2 (4000);
    v_temp1         VARCHAR2 (200);
    tab_pqr_tid_sumamt pqr_tid_sumamt_tab := pqr_tid_sumamt_tab();
    tab_xyztab_ptstab  xyztab_ptstab_tab  := xyztab_ptstab_tab();
    ret_cur sys_refcursor;
BEGIN
    FOR varcursor_rec IN varcursor
    loop
        v_temp1 := varcursor_rec.p_type; --p_type contains column name of the pqr TABLE
        v_temp :=
            'SELECT T_ID,SUM(AMOUNT) OVER (PARTITION BY '     
            || v_temp1     
            || ' ORDER BY '     
            || v_temp1     
            || ') total from pqr';
--        dbms_output.put_line('v_temp: '||v_temp);
        OPEN v_ref FOR v_temp;  
        loop
            fetch v_ref INTO v_t_id,v_total;
            exit WHEN v_ref%notfound;

            IF varcursor_rec.p_amount < v_total THEN
                tab_pqr_tid_sumamt.EXTEND;
                -- cast the cursor values into the record type to be added to the table type
                tab_pqr_tid_sumamt( tab_pqr_tid_sumamt.count ) := pqr_tid_sumamt_rec(v_t_id, v_total);
            END IF;
        END loop;
        tab_xyztab_ptstab.EXTEND;
        -- cast the cursor values and nested table type to the record type and add to the table type
        tab_xyztab_ptstab(tab_xyztab_ptstab.count) := xyztab_ptstab_rec (varcursor_rec.xyz_id, varcursor_rec.p_type, varcursor_rec.p_amount, tab_pqr_tid_sumamt);
    END loop;

    --open the return refcursor
    OPEN ret_cur FOR 
        SELECT xyztab_ptstab_rec(xyz_id, p_type, p_amount, p_pqr_tid_sumamt_tab) FROM TABLE( tab_xyztab_ptstab );

    -- return the refcursor
    RETURN ret_cur;
END xyz_pqr_refcursor;

Now, let's test the function:

DECLARE
    test_cur      sys_refcursor;
    test_rec      xyztab_ptstab_rec;
    test_pqrtab   pqr_tid_sumamt_tab;
    counter       int := 1;
BEGIN
    test_cur := xyz_pqr_refcursor();
    loop
        fetch test_cur INTO test_rec;
        exit WHEN test_cur%notfound;
        dbms_output.put_line('test_rec('||counter||') -- xyz_id: '||test_rec.xyz_id||', p_type: '||test_rec.p_type||', p_amount: '||test_rec.p_amount);
        test_pqrtab := test_rec.p_pqr_tid_sumamt_tab;
        FOR j IN 1 .. test_pqrtab.count
        loop
            dbms_output.put_line('.... test_pqrtab('||j||') - t_id: '||test_pqrtab(j).t_id||', sumamt: '||test_pqrtab(j).sum_amount);
        END loop;
        counter := counter + 1;
    END loop;
EXCEPTION 
    WHEN others THEN dbms_output.put_line('whoops: '||sqlerrm);
END;

Test results:

test_rec(1) -- xyz_id: p_1, p_type: p_id, p_amount: 100000
test_rec(2) -- xyz_id: p_2, p_type: p_id,t_status, p_amount: 100
.... test_pqrtab(1) - t_id: 3, sumamt: 300
.... test_pqrtab(2) - t_id: 5, sumamt: 300
.... test_pqrtab(3) - t_id: 4, sumamt: 500
.... test_pqrtab(4) - t_id: 2, sumamt: 500

Alternatively, you could just return the declared table type itself instead of a sys_refcursor.

I hope this helps.