将两个汇总查询合并为一个

Question

For some context, I am making an image browser which is connected to an SQLite database. Within the browser, similar images are grouped into an event (EventId) and each image (MicrosoftId) is labelled with a few tags (name) .

I have these two queries on the same table ( TagsMSCV ) but pulling out different information. Ultimately I need to combine the information in my browser so if it was possible to combine these two queries (maybe with a JOIN?) it would be a lot faster and convenient for me. Both results of these queries share the EventId column.

1st Query ():

SELECT EventId as 'event', count(*) as 'size',
    SUM(case when tag_count = 1 then 1 else 0 end) as '1',
    SUM(case when tag_count = 2 then 1 else 0 end) as '2',
    SUM(case when tag_count = 3 then 1 else 0 end) as '3'
FROM (SELECT EventId, MicrosoftId,
SUM(case when name in ('indoor', 'cluttered', 'screen') then 1 else 0 end) as tag_count 
FROM TagsMSCV GROUP BY EventId, MicrosoftId) TagsMSCV
GROUP BY EventId ORDER BY 3 DESC, 2 DESC, 1 DESC

2nd Query

SELECT EventId,
    SUM(CASE WHEN name = 'indoor' THEN 1 ELSE 0 END) as indoor,
    SUM(CASE WHEN name = 'cluttered' THEN 1 ELSE 0 END) as cluttered,
    SUM(CASE WHEN name = 'screen' THEN 1 ELSE 0 END) as screen
FROM TagsMSCV WHERE name IN ('indoor', 'cluttered', 'screen')
GROUP BY EventId

As you can see in both queries I am feeding in the tags 'necktie' 'man', 'male' and getting different information back.

SQL Fiddle Here: https://www.db-fiddle.com/f/f8WNimjmZAj1XXeCj4PHB8/3

Answer 1

You could use an Inner join subquery

SELECT TagsMSCV.EventId as 'event', count(*) as 'size',
    SUM(case when tag_count = 1 then 1 else 0 end) as '1',
    SUM(case when tag_count = 2 then 1 else 0 end) as '2',
    SUM(case when tag_count = 3 then 1 else 0 end) as '3',
    t.necktie, 
    t.man,
    t.male
FROM (
  SELECT EventId, MicrosoftId,
  SUM(case when name in ('necktie' 'man', 'male') then 1 else 0 end) as tag_count 
  FROM TagsMSCV GROUP BY EventId, MicrosoftId
) TagsMSCV
INNER JOIN (
  SELECT EventId,
      SUM(CASE WHEN name = 'necktie' THEN 1 ELSE 0 END) as necktie,
      SUM(CASE WHEN name = 'man' THEN 1 ELSE 0 END) as man,
      SUM(CASE WHEN name = 'male' THEN 1 ELSE 0 END) as male
  FROM TagsMSCV WHERE name IN ('necktie' 'man', 'male')
  GROUP BY EventId
) t on t.EventId = TagsMSCV.EventId 
GROUP BY TagsMSCV.EventId 
ORDER BY 3 DESC, 2 DESC, 1 DESC

Answer 2

You should do this all in one query:

SELECT EventId as event, count(*) as size,
       SUM(case when (indoor + cluttered + screen) = 1 then 1 else 0 end) as tc_1,
       SUM(case when (indoor + cluttered + screen) = 2 then 1 else 0 end) as tc_2,
       SUM(case when (indoor + cluttered + screen) = 3 then 1 else 0 end) as tc_3,
       SUM(indoor) as indoor,
       SUM(cluttered) as cluttered,
       SUM(screen) as screen
FROM (SELECT EventId, MicrosoftId,
             SUM(CASE WHEN name = 'indoor' THEN 1 ELSE 0 END) as indoor,
             SUM(CASE WHEN name = 'cluttered' THEN 1 ELSE 0 END) as cluttered,
             SUM(CASE WHEN name = 'screen' THEN 1 ELSE 0 END) as screen
      FROM TagsMSCV
      GROUP BY EventId, MicrosoftId
     ) TagsMSCV
GROUP BY EventId
ORDER BY 3 DESC, 2 DESC, 1 DESC;

You need two aggregations to get the information about the tag counts. There is no need to add more aggregations and joins to the query.