这可以在1个mysql查询中做吗

Question

I'm trying to get all the app names from this table

SELECT id, name FROM app_names

And using that data fetch these results

SELECT count(*) FROM users_dailyrecords WHERE day='x' appName='THE ID FROM THE SELECT ABOVE'

And with the result of that query I want to insert it into

INSERT INTO app_stats (appID, day, totalUsers) VALUES ('appID', 'x', 'RESULT FROM count(*)')

I could easily write a php script to do this but I think it can be done pretty easily using mysql queries.

Answer 1

Yes, you can combine all of these:

INSERT INTO app_stats(appID, day, totalUsers) 
    SELECT 'appID', 'x', count(*)
    FROM users_dailyrecords
     WHERE day = 'x' AND
           appName IN (name FROM app_names);

It is unclear what the appName part is doing. Presumably, the only appnames in users_dailyrecords should be valid ones in appName . This sounds like a good place for a foreign key relationship.