PostgreSQL-按jsonb列分组 [英] PostgreSQL - grouping by jsonb column

问题描述

我有survey_results表，该表具有以下列:

I have survey_results table which has following columns:

id - integer
score_labels - jsonb

score_labels列数据格式如下:

{"total": "High", "risk": "High"}

{"total": "High", "risk": "High"}

现在，我想拥有一个SQL查询，该查询将通过此score_labels列对我的调查结果进行分组和计数.最终结果应该是这样:

Now I want to have sql query that will group and count my survey results by this score_labels column. This is what the final result should look like:

total                          risk
-------                        ------
{high: 2, medium: 1, low: 0}   {high: 1, medium: 2, low: 1}

我想通过得分标签来统计调查结果.有没有办法在PostgreSQL中做到这一点?

I want to count survey results by its score labels. Is there way to do it in PostgreSQL?

这是具有以下架构的简单sqlfiddle:

Here is simple sqlfiddle with the following schema:

http://sqlfiddle.com/#!17/0367f/1/0

推荐答案

一种有点复杂的聚合:

with my_table (id, score_labels) as (
values
(1, '{"total": "High", "risk": "High"}'::jsonb),
(2, '{"total": "High", "risk": "Low"}'::jsonb),
(3, '{"total": "Low", "risk": "Medium"}'::jsonb)
)

select 
    jsonb_build_object(
        'high', count(*) filter (where total = 'High'),
        'medium', count(*) filter (where total = 'Medium'),
        'low', count(*) filter (where total = 'Low')
    ) as total,
    jsonb_build_object(
        'high', count(*) filter (where risk = 'High'),
        'medium', count(*) filter (where risk = 'Medium'),
        'low', count(*) filter (where risk = 'Low')
    ) as risk
from (
    select 
        score_labels->>'total' as total, 
        score_labels->>'risk' as risk
    from my_table
    ) s

               total                |                risk                
------------------------------------+------------------------------------
 {"low": 1, "high": 2, "medium": 0} | {"low": 1, "high": 1, "medium": 1}
(1 row) 

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