Question

I have this big code where I want 3 things in my search:
1- look for all the orders (delivered and not) that match the search:
2- look for all the pendent orders that match the search;
3- look for all the delivered orders that match the search;

create or replace
function search_order(search IN VARCHAR2, a_option NUMBER) RETURN types.ref_cursor
AS
    orders_cursor types.ref_cursor;

BEGIN
    if search is not null then
      if a_option = 0 then /*case 1*/
         OPEN orders_cursor FOR
          select value(f), value(p),i.qtd_if, i.prec_total_if , forn.nome_fornecedor
              from item_fornecimento i, produto p ,fornecimento f, fornecedor forn
              where f.id_fornecimento in (select f.id_fornecimento from fornecimento f where f.id_fornecedor in 
             (select f1.id_fornecedor from fornecedor  f1 where f1.nome_fornecedor LIKE '%'||search||'%')) 
              and f.id_fornecimento= i.id_fornecimento and i.id_prod= p.id_prod and
              f.id_fornecedor = forn.id_fornecedor
              order by forn.nome_fornecedor,f.data_encomenda desc,p.nome_prod asc;  
        RETURN orders_cursor;


      ELSIF a_option = 1 then /*case 2*/
        OPEN orders_cursor FOR
        (...)
            where f.id_fornecimento in (select f.id_fornecimento from fornecimento f where f.id_fornecedor in 
            (select f1.id_fornecedor from fornecedor  f1 where f1.nome_fornecedor LIKE '%'||search||'%')and f.data_entrega is null) 
            (...) 
        RETURN orders_cursor;

        ELSE /* case 3*/
        OPEN orders_cursor FOR
          (...)
              where f.id_fornecimento in (select f.id_fornecimento from fornecimento f where f.id_fornecedor in 
              (select f1.id_fornecedor from fornecedor  f1 where f1.nome_fornecedor LIKE '%'||search||'%')and f.data_entrega is not null) 
              (...) 
          RETURN orders_cursor;    
      end if;
    end if;

END;

This works if my search is not null, but if it is I would like just to modify a little bit the inner select and turn it into something like this:
(select f1.id_fornecedor from fornecedor f1 where f1.nome_fornecedor LIKE '%'||search||'%')and f.data_entrega is not null) to –> (select f1.id_fornecedor from fornecedor f1)and f.data_entrega is not null)

So I have 3 conditions for search, and I would like to know if it’s possible to use something like case, decode or even another cursor with a parameter, to do this inner select with:
– LIKE if the search string is not null;
– without LIKE, if the string is null;

But I haven’t seen any examples of this and things can really go quite messy.
Could someone help a newbie with same code?

Answer 1

I too would use dynamic SQL for this, but you can use a PLSQL case to control execution flow:

BEGIN

  CASE
    WHEN search IS NOT NULL AND a_option = 0 THEN
      OPEN orders_cursor FOR
        SELECT VALUE(f), 
               VALUE(p),
               i.qtd_if, 
               i.prec_total_if, 
               forn.nome_fornecedor
          FROM ITEM_FORNECIMENTO i
          JOIN PRODUTO p ON p.id_prod = i.id_prod
          JOIN FORNECIMENTO f ON f.id_fornecimento = i.id_fornecimento
          JOIN FORNECEDOR forn ON forn.id_fornecedor = f.id_fornecedor
                              AND forn.nome_fornecedor LIKE '%'||search||'%'
      ORDER BY forn.nome_fornecedor,f.data_encomenda desc,p.nome_prod;

    WHEN search IS NULL AND a_option = 1 THEN
      OPEN orders_cursor FOR
        SELECT VALUE(f), 
               VALUE(p),
               i.qtd_if, 
               i.prec_total_if, 
               forn.nome_fornecedor
          FROM ITEM_FORNECIMENTO i
          JOIN PRODUTO p ON p.id_prod = i.id_prod
          JOIN FORNECIMENTO f ON f.id_fornecimento = i.id_fornecimento
                             AND f.data_entrega IS NULL
          JOIN FORNECEDOR forn ON forn.id_fornecedor = f.id_fornecedor
      ORDER BY forn.nome_fornecedor,f.data_encomenda desc,p.nome_prod;

    WHEN search IS NOT NULL AND a_option = 1 THEN
      OPEN orders_cursor FOR
        SELECT VALUE(f), 
               VALUE(p),
               i.qtd_if, 
               i.prec_total_if, 
               forn.nome_fornecedor
          FROM ITEM_FORNECIMENTO i
          JOIN PRODUTO p ON p.id_prod = i.id_prod
          JOIN FORNECIMENTO f ON f.id_fornecimento = i.id_fornecimento
                             AND f.data_entrega IS NULL
          JOIN FORNECEDOR forn ON forn.id_fornecedor = f.id_fornecedor
                              AND forn.nome_fornecedor LIKE '%'||search||'%'
      ORDER BY forn.nome_fornecedor,f.data_encomenda desc,p.nome_prod;
  END CASE;

END;

It’s not complete, but you get the idea. I also converting your ANSI-89 JOIN syntax to ANSI-92, and got rid of the IN clauses in the process.