Question

我有一个包含名称及其交易的数据集，如何获得比平均值更低的平均值和交易数量，并且低于平均值。

Name    Transaction
John    12
John    34
John    45
John    66
John    32
chris   26
chris   54
chris   56
chris   99
chris   13
chris   4
kim     22
kim     34
kim     7
kim     11
kim     34

O / P将是

Name      Avg     Count_greater_than_Avg    Count_Less_than_Avg
John      37.8          2                           3
chris     42            3                           3
kim       21.6          3                           2

提前致谢..

Answer 1

试试这个：

SELECT t1.Name, t2.Aver,
       COUNT(CASE WHEN Transaction < Aver THEN 1 END) Count_Less_than_Avg,
       COUNT(CASE WHEN Transaction > Aver THEN 1 END) Count_greater_than_Avg
FROM mytable AS t1
JOIN (
  SELECT Name, AVG(Transaction * 1.0) AS Aver
  FROM mytable
  GROUP BY Name
) AS t2 ON t1.Name = t2.Name
GROUP By Name

您需要派生表才能计算每Name的平均值。然后，您可以JOIN原始表到此派生表并使用条件聚合来计算小于，大于的数字交易。

Demo here

Answer 2

这基本上首先使用相关查询添加列Your_Avg，然后用另一个选择包装它以选择小于avg和更大倍数的出现次数。

SELECT tt.name,tt.Your_Avg,
       count(CASE WHEN tt.Your_Avg > tt.Transaction then 1 end) as Greater_Then_Avg,
       count(CASE WHEN tt.Your_Avg > tt.Transaction then 1 end) as Smaller_Then_Avg
FROM(
    SELECT t.name,
           (SELECT avg(s.transaction) FROM YourTable s WHERE s.name = t.name) as Your_Avg,
           t.transaction
    FROM YourTable) tt
GROUP BY tt.name

如何按名称计算大于和小于平均值的计数

2 个答案: