Question

我有一个表，其中包含重复名称，得分值和得分类型的列表。如何按名称分组，获取每种分数类型的每个名称的分数值的平均值，然后将此平均值添加到我创建的称为avg_score的浮点列中？示例：

NAME        SCORE_TYPE       SCORE_VALUE     AVG_SCORE << Desired Output

bob         base_score       5               4
bob         base_score       4               4 
bob         base_score       3               4
bob         revised_score    1               3
bob         revised_score    5               3
bob         revised_score    3               3 
jack        base_score       5               5
jack        base_score       7               5 
jack        base_score       3               5
jack        revised_score    1               1
jack        revised_score    1               1
jack        revised_score    1               1

Answer 1

使用窗口功能

select *, 
avg(SCORE_VALUE) over(partition by NAME,SCORE_TYPE) as AVG_SCORE from t

Answer 2

select
name
,score_type
,score_value
,avg(score_value) over(partition by name,score_type) as AVG_SCORE
from [table name]

Answer 3

如果要将其添加到表中，则需要update：

update t
    set AVG_SCORE = tt.avg_score
    from (select name, score_type, avg(score) as avg_score
          from t
          group by name, score_type
         ) tt
    where tt.name = t.name and tt.score_type = t.score_type;

将平均值添加到PostgreSQL中每个组的列

3 个答案: