Re: To store or calculate on the spot?

[Rick James]

(MySQL has nothing automatic.)
The simple approach is for the nightly cron job to do

INSERT INTO SummaryTable
    SELECT datetime,b,c COUNT(*), SUM(xx), ... 
        FROM MainTable
        WHERE datetime >= CURRENT_DATE() - INTERVAL 1 DAY
          AND datetime < CURRENT_DATE()
        GROUP BY LEFT(10, datetime, 10),b,c;

(This assumes that you have a datetime field -- LEFT(...,10) is one way to turn that into just a date.