sqlalchemy case when分组查询统计

1.需求

根据过滤条件将设备按升级状态分组，统计总数和各个状态的数量。

2.原始数据

3.原生sql语句

select 
	count(*) as "total",
	sum(case when upgrade_status='failed' then 1 else 0 end) as "failed_count",
	sum(case when upgrade_status='unstarted' then 1 else 0 end) as "unstarted_count",
	sum(case when upgrade_status='cancelled' then 1 else 0 end) as "cancelled_count",
	sum(case when upgrade_status='upgrading' then 1 else 0 end) as "upgrading_count",
	sum(case when upgrade_status='succeed' then 1 else 0 end) as "succeed_count"
from edge_ota_record 
where task_id='73860eaffb014dba80db2f67518d5994' 
GROUP BY upgrade_status;

结果：

3.使用sqlalchemy

from sqlalchemy import func, case

statistics_dict = {}
qs = self.session.query(
                func.count().label("total"),
                func.sum(case(whens=[(self.model.upgrade_status == 'unstarted', 1)],else_=0)).label("unstarted_count"),
                func.sum(case(whens=[(self.model.upgrade_status == 'succeed', 1)],else_=0)).label("succeed_count"),
                func.sum(case(whens=[(self.model.upgrade_status == 'failed', 1)],else_=0)).label("failed_count"),
                func.sum(case(whens=[(self.model.upgrade_status == 'cancelled', 1)],else_=0)).label("cancelled_count"),
                func.sum(case(whens=[(self.model.upgrade_status == 'upgrading', 1)],else_=0)).label("upgrading_count"),
            ).filter(self.model.task_id == task_id).group_by(self.model.upgrade_status)
            
results = [dict(zip(result.keys(), result)) for result in qs.all()]

counter = collections.Counter()
for result_dict in results:
	counter.update(result_dict)
statistics_dict.update(dict(counter))

print(statistics_dict )

结果：

 # {"total": 18, "unstarted_count": 18, "upgrading_count": 0, "cancelled_count": 0, "failed_count": 0, "succeed_count": 0}

最后

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