Sql 如何按日期计数枚举和分组

我有一个表，它有一个日期列和一个用户类型列。如何获得按日期分组的用户类型计数

表-用户日期

Date         user_type

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期望结果

Date        Customer Sales
09/20/2020   2         2
09/21/2020   1         1

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在标准SQL中，您可以使用：

select date,
       sum(case when user_type = 'Sales' then 1 else 0 end) as sales,
       sum(case when user_type = 'Customer' then 1 else 0 end) as customer
from t
group by date;

这是几乎所有数据库都支持的标准语法。有些数据库有快捷方式

在Postgres中，我会这样说：

select date,
       count(*) filter (where user_type = 'Sales') as sales,
       count(*) filter (where user_type = 'Customer') as customer
from t
group by date;

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我删除了不一致的数据库标记。请标记您真正使用的数据库。这正是我想要的。非常感谢，戈登。

select date,
       count(*) filter (where user_type = 'Sales') as sales,
       count(*) filter (where user_type = 'Customer') as customer
from t
group by date;