Re-writing the query in 11g

Question

Hello,
Can someone suggest an idea to rewrite this query? this query is taking longer time as expected probably
they way the query is formed is not right? Thanks in advance! I use 11g
SELECT   brand_id,
                      region_id,
                      sku_base_id,
                      desc_key,
                      (SELECT   MAX (cps.product_code)
                         FROM   cat_prod_sku_vw cps
                        WHERE       cps.brand_id = srl.brand_id
                                AND cps.region_id = srl.region_id
                                AND cps.brand_id = 4
                                AND cps.region_id = 0
                                AND (   cps.parent_cat_id
                                     || 'PROD'
                                     || cps.prod_base_id) = srl.desc_text)
                         AS desc_text
               FROM   sku_rgn_lang_vw srl
              WHERE       brand_id = 4
                      AND region_id = 0
                      AND desc_key LIKE 'www_pcode_%'
                      AND LENGTH (desc_text) > 6
                      AND desc_text LIKE 'CAT%' ;

Answer 1

You should look at this thread {message:id=9360003} to get an idea of what other information is required.
However, I would be inclined to re-write it as a (outer) join instead of a scalar select. Somethign more like:
SELECT srl.brand_id, srl.region_id, srl.sku_base_id, srl.desc_key,
       cps.desc_text
FROM sku_rgn_lang_vw srl
   left join (SELECT brand_id, region_id,
                     parent_cat_id||'PROD'||prod_base_id desc_text
                     MAX (product_code) product_code
              FROM cat_prod_sku_vw cps
              WHERE brand_id = 4
                AND region_id = 0
              GROUP BY brand_id, region_id,
                       parent_cat_id||'PROD'||prod_base_id) cps
      on cps.brand_id = srl.brand_id AND
         cps.region_id = srl.region_id AND
         cps.parent_cat_id||'PROD'||cps.prod_base_id = srl.desc_text
WHERE srl.brand_id = 4
  AND srl.region_id = 0
  AND srl.desc_key LIKE 'www_pcode_%'
  AND LENGTH (cps.desc_text) > 6
  AND cps.desc_text LIKE 'CAT%' ;Although, I'm not entirely sure I got all of the aliases correct.
John