SQL PLUS-顯示錶

Question

我需要編寫一個查詢，顯示了品牌標識，品牌名稱，品牌類型，產品的平均價格爲具有最大平均產品價格

我能得到平均的品牌價格的所有品牌通過輸入：

SQL> SELECT LGPRODUCT.BRAND_ID, BRAND_NAME, BRAND_TYPE, ROUND(AVG(PROD_PRICE),2) 
FROM BOFF.LGPRODUCT, BOFF.LGBRAND 
WHERE LGPRODUCT.BRAND_ID = LGBRAND.BRAND_ID 
GROUP BY LGPRODUCT.BRAND_ID, BRAND_NAME, BRAND_TYPE 
ORDER BY LGPRODUCT.BRAND_ID; 

但如果我進入ROUND（MAX（AVG（PROD_PRICE）），2）我得到一個錯誤，有什麼建議？

Answer 1

您可以使用窗口函數rank標記根據平均的隊伍，然後過濾，以獲得最高等級行：

select * 
from (
    select lgproduct.brand_id, 
     brand_name, 
     brand_type, 
     round(avg(prod_price), 2), 
     rank() over (
      order by round(avg(prod_price), 2) desc 
      ) as rnk 
    from boff.lgproduct, 
     boff.lgbrand 
    where lgproduct.brand_id = lgbrand.brand_id 
    group by lgproduct.brand_id, 
     brand_name, 
     brand_type 
    ) t 
where rnk = 1 
order by brand_id; 

如果你必須使用having然後嘗試：

select lgproduct.brand_id, 
    brand_name, 
    brand_type, 
    round(avg(prod_price), 2) 
from boff.lgproduct, 
    boff.lgbrand 
where lgproduct.brand_id = lgbrand.brand_id 
group by lgproduct.brand_id, 
    brand_name, 
    brand_type 
having round(avg(prod_price), 2) = (
     select max(round(avg(prod_price), 2)) 
     from boff.lgproduct, 
      boff.lgbrand 
     where lgproduct.brand_id = lgbrand.brand_id 
     group by lgproduct.brand_id, 
      brand_name, 
      brand_type 
     ) 
order by lgproduct.brand_id;