Oracle 11g Release 2

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CREATE TABLE bb_sales_sum (
    idProduct number(2) NOT NULL,
    total number(6,2),
    quantity number); 







create table bb_basket (orderplaced int,idproduct number(2), quantity number,total number);
insert into bb_basket(idproduct,orderplaced,quantity,total) VALUES(1,null,3,12);
1 rows affected

select * from bb_basket;


ORDERPLACED
IDPRODUCT
QUANTITY
TOTAL


null
1
3
12


    CREATE OR REPLACE TRIGGER bb_salesum_trg
        AFTER UPDATE OF orderplaced on bb_basket 
          FOR EACH ROW
        WHEN (NEW.orderplaced = 1)
    
    BEGIN   
      MERGE INTO bb_sales_sum t USING 
      ( select :new.idproduct as idproduct ,
               :new.quantity  as quantity,
               :new.total     as total 
               from dual ) s  
         ON (s.idproduct = t.idproduct ) 
             WHEN MATCHED THEN UPDATE
                SET  quantity  = s.quantity,
                     total     = s.total
              WHEN NOT MATCHED THEN
         INSERT (
              idproduct,quantity,total)
         VALUES
              ( :new.idproduct,:new.quantity,:new.total );
    END;
    /
update bb_basket set orderplaced = 1 where idproduct = 1;
1 rows affected

select * from bb_sales_sum;


IDPRODUCT
TOTAL
QUANTITY


1
12
3