在子查詢中添加第二個外部查詢

Question

我在下面有一個查詢，它給了我中位數，我想把我的count(*)放在一個單獨的子查詢中，它計算我在中位數計算中使用的總行數（因為它運行得更好一些）。 最好的方法是什么？ 謝謝！

 SELECT our_id, AVG(1.0 * our_val) as Median
FROM
( SELECT our_id, our_val, 
  COUNT(*) OVER (PARTITION BY our_id) AS cnt,
  ROW_NUMBER() OVER (PARTITION BY our_id ORDER BY our_val) AS rn
  FROM our_table
) AS x
WHERE rn IN ((cnt + 1)/2, (cnt + 2)/2) GROUP BY our_id;

Answer 1

您正在計算子查詢中的count(*) 。 為什么不直接使用它？

SELECT our_id, AVG(1.0 * our_val) as Median, cnt
FROM (SELECT our_id, our_val, 
             COUNT(*) OVER (PARTITION BY our_id) AS cnt,
             ROW_NUMBER() OVER (PARTITION BY our_id ORDER BY our_val) AS rn
      FROM our_table
     ) x
WHERE rn IN ((cnt + 1)/2, (cnt + 2)/2)
GROUP BY our_id, cnt;