[英]Get "group by" parameter column name/ alias from another table
I have a table podcast
.我有一个桌面
podcast
。 Each podcast has category and subcategory associated to it in the form of ids.每个播客都有以 id 形式与之关联的类别和子类别。
This category_id and subcategory_id have their name values in their respective tables -这个 category_id 和 subcategory_id 在它们各自的表中有它们的名称值 -
Now, I want to get the count of podcasts under each category, subcategory combination -现在,我想获取每个类别、子类别组合下的播客数量 -
SELECT podcast_category_id, podcast_subcategory_id, count(*)
FROM podcasts
where podcast_owner = 14 AND podcast_upload_time_stamp >= timestamp '2020-10-22 00:00:00'
GROUP BY podcast_category_id, podcast_subcategory_id
Output -输出 -
The output shows podcast_category_id
and podcast_subcategory_id
columns as expected.输出按预期显示
podcast_category_id
和podcast_subcategory_id
列。 However, I want to replace podcast_category_id
with category_name
and podcast_subcategory_id
with sub_category_name
.不过,我想替换
podcast_category_id
与category_name
和podcast_subcategory_id
与sub_category_name
。 How do I do that?我怎么做?
Join to those tables.加入这些表。
SELECT c.category_name, sc.sub_category_name, count(p.*)
FROM podcasts p
join categories c
on c.category_id = p.podcast_category_id
join sub_categories sc
on sc.sub_category_id = p.podcast_subcategory_id
where p.podcast_owner = 14
AND p.podcast_upload_time_stamp >= timestamp '2020-10-22 00:00:00'
GROUP BY 1,2
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