怎样合并分支条件，减少代码行数？

w怎样合并分支条件，减少代码行数？

DROP PROCEDURE IF EXISTS w_self_update_amzasin;
DELIMITER /w/
CREATE PROCEDURE w_self_update_amzasin()
BEGIN
  DECLARE done INT DEFAULT FALSE;
  DECLARE w_pkid INT;
  DECLARE w_asin VARCHAR(16);
  DECLARE w_country VARCHAR(6); 
  DECLARE wcur CURSOR FOR SELECT pkid,asin,country FROM amzasin;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

  OPEN wcur;
  read_loop: LOOP
    FETCH wcur INTO w_pkid,w_asin,w_country;
    IF done THEN LEAVE read_loop;
    END IF;
        SET @w_nothhtps='www.amazon.';  
        SET @w_most=CONCAT(LOWER(w_country),'/product/dp/',w_asin);
        CASE  LOWER(w_country)
            WHEN 'ca' THEN SELECT 'w'; 
            WHEN 'in' THEN SELECT 'w'; 
            WHEN 'es' THEN SELECT 'w'; 
            WHEN 'it' THEN SELECT 'w'; 
            WHEN 'fr' THEN SELECT 'w'; 

            WHEN 'jp' THEN SET @w_most=CONCAT('co.',@w_most); 
            WHEN 'uk' THEN SET @w_most=CONCAT('co.',@w_most); 

            WHEN 'mx' THEN SET @w_most=CONCAT('com.',@w_most); 

            WHEN 'us' THEN SET @w_most=CONCAT('com/gp/product/',w_asin); 
      ELSE
        BEGIN
        END;
    END CASE;

        SET @w_nothhtps=CONCAT(@w_nothhtps,@w_most);
        SET @wtmp=CONCAT('UPDATE amzasin ',' SET url="',@w_nothhtps,'" WHERE pkid=',w_pkid);
        PREPARE  stmt FROM @wtmp ;
        EXECUTE  stmt ;
        DROP PREPARE stmt;
  END LOOP;
  CLOSE wcur;
END/w/
DELIMITER;
CALL w_self_update_amzasin(); 

ERROR

DROP PROCEDURE IF EXISTS w_self_update_minerasinlist_minerasinlist;
DELIMITER /w/
CREATE PROCEDURE w_self_update_minerasinlist()
BEGIN
  DECLARE done INT DEFAULT FALSE;
  DECLARE w_autoid INT;
  DECLARE w_asin VARCHAR(16);
  DECLARE w_countrycode VARCHAR(6); 
  DECLARE wcur CURSOR FOR SELECT autoid,asin,countrycode FROM minerasinlist;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

  OPEN wcur;
  read_loop: LOOP
    FETCH wcur INTO w_autoid,w_asin,w_countrycode;
    IF done THEN LEAVE read_loop;
    END IF;
        SET @w_nothhtps='www.amazon.';  
        SET @w_most=CONCAT(LOWER(w_countrycode),'/product/dp/',w_asin);
        CASE  LOWER(w_countrycode)
                WHEN 'ca' 
                WHEN 'in' 
                WHEN 'es' 
                WHEN 'it' 
                WHEN 'fr' THEN SELECT 'w'; 

                WHEN 'jp' 
                WHEN 'uk' THEN SET @w_most=CONCAT('co.',@w_most); 

                WHEN 'mx' THEN SET @w_most=CONCAT('com.',@w_most); 

                WHEN 'us' THEN SET @w_most=CONCAT('com/gp/product/',w_asin); 
      ELSE
        BEGIN
        END;
    END CASE;

        SET @w_nothhtps=CONCAT(@w_nothhtps,@w_most);
        SET @wtmp = CONCAT('UPDATE minerasinlist ',' SET url="',@w_nothhtps,'" WHERE autoid=',w_autoid);
        PREPARE  stmt FROM @wtmp ;
        EXECUTE  stmt ;
        DROP PREPARE stmt;
  END LOOP;
  CLOSE wcur;
END/w/
DELIMITER;
CALL w_self_update_minerasinlist( );