在 hivesql 中查找唯一计数 Postgresql 查询

编程问答 2022-05-23

问题描述

我想获得唯一客户数。我有 postgresql 查询的参考。您能否将此查询转换为 Hivesql

SELECT
    COUNT(user_id) Total_profiles,COUNT(distinct user_id) FITLER (WHERE age BETWEEN 18 AND 12) as age_less_than_20
FROM 
    customer_profiles
WHERE 
    profile_date BETWEEN '2020-01-01' AND '2020-12-31'

解决方法

用例表达式：

SELECT
    COUNT(user_id) Total_profiles,COUNT(distinct case when age BETWEEN 18 AND 12 then user_id else null end) as age_less_than_20
FROM 
    customer_profiles
WHERE 
    profile_date BETWEEN '2020-01-01' AND '2020-12-31'

另一种计算distinct的方法是size(collect_set())：

SELECT
    COUNT(user_id) Total_profiles,size(collect_set(case when age BETWEEN 18 AND 12 then user_id else null end)) as age_less_than_20
FROM 
    customer_profiles
WHERE 
    profile_date BETWEEN '2020-01-01' AND '2020-12-31'
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