问题
I work in a lightrail-company, and I am responsible for the passenger counting. We have automatic passenger counting on one tram, but we have 16 trams at the most in traffic. I am looking for a way to multiply sum of boarded passengers and number of trams in traffic.
I have a MYSQL database, "Telledata".
I have two tables, "tram_usage_fri", this is a table who shows how many trams that are in use at any given time of the day.
and "Vogn217", which has all the information about passenger counting.
.
Lets take an example:
Table tram_usage_fri: Between 14:10 and 17:41 we have 16 trams in traffic.
Table Vogn 217: I want to summarize number of passengers between 14:10 and 17:41 and multiply this by 16 trams from table "tram_usage_fri".
Is this even possible?
来源：https://stackoverflow.com/questions/33916408/summarize-and-multiplication-between-tables