mysql查詢來計算板球擊球手的平均值

Question

我有一個mysql表，它包含這樣的數據。

Name |how_out |runs 
------------------------------ 
Robin |Not out |45 
Robin |lbw  |25 
Robin |caught  |50 
Robin |caught  |0 
Robin |bowled  |30 
Robin |bowled  |0 
. 
. 
. 

我想要一個SQL查詢，它返回以下列

名稱，Total_runs，平均

聽起來很簡單，但對我來說唯一的問題是。 在板球，平均是不SUM（運行）/ COUNT（*） 它的總和（運行）/局的數字的計數，其中how_out不是「不出來」

能有一個人告訴我如何寫一個這樣的查詢？

我寫的查詢出於明顯原因給出了錯誤的平均值。 我寫的查詢是

Select `Name`,sum(`runs`) as 'Total_runs', Sum(`runs`)/count(*) 
From `batsman_stats` 
group by `Name` 
order by 2 desc 

請問sql專家請幫幫我嗎？

感謝

Answer 1

Select `Name`,sum(`runs`) as 'Total_runs', Sum(`runs`)/sum(if(how_out <> 'Not out',1,0)) 
From `batsman_stats` 
group by `Name` 
order by 2 desc 

Answer 2

You could use a CASE statement：

SELECT Name, 
     SUM(Runs) as Total_runs, 
     SUM(Runs)/COUNT(CASE WHEN how_out <> 'Not out' THEN 1 END) as Average 
FROM batsman_stats 
GROUP BY Name 
ORDER BY SUM(Runs) DESC 

Answer 3

我想你需要一個子查詢：

Select Name, sum(runs) as Total_runs, Sum(runs)/(
    select count(*) from batsman_stats b 
    where b.Name=a.Name and not b.how_out = 'Not out' 
) 
From batsman_stats a 
group by Name 
order by 2 desc