如何从 table 添加一列，即计数（*）？

Question

我有一个 table ，它只包含两列： session_id, word_id ， table 是 session_word

我们可以得到两个值作为下面的 sql 查询：

select count(*) as sum_word_freq from session_word
select count(distinct session_id) as sum_session_freq from session_word

我已经建立了 table 作为

select word_id, count(*) as word_freq , count(distinct session_id) as word_session_freq
    from session_word
    group by word_id

但我想将结果包含在另外两列中：sum_word_freq 和 sum_session_freq。我怎样才能在完整的 sql 查询中实现它。

Answer 1

如果您希望在单个查询中按不同组进行聚合，则使用分析函数是解决方案：

select
        word_id, 
        word_freq, 
        word_session_freq,
        --the sum for all dataset
        sum(word_freq)         over() as sum_word_freq,
        sum(word_session_freq) over() as sum_session_freq
from
(
 select word_id, 
        count(*)                   as word_freq, 
        count(distinct session_id) as word_session_freq
    from session_word
    group by word_id
)s;

如何从 table 添加一列，即计数（*）？

How to add one column which is the count(*) from the table?

sql

hive

aggregate

hiveql