在子查询中添加第二个外部查询

Question

I have a query below that gives me median, I want to put my count(*) that counts the total # of rows that I use in my median calculation in a seperate subquery (since it runs a bit better that way). What is the best way to do that? Thank you!

 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

You are calculating count(*) in the subquery. Why not just use that?

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;