Question

I am writing a query for my database and basically I want to query a database for events happening in each room. Meaning that i want to find the earliest event happening in room 1 and the earliest event happening in room 2.

Below I have the code for performing this query for 1 room. This code only returns the earliest event in room 2. How can I perform a query where I find the earliest event for room 1 and the earliest event for room 2 and return it in a single query?

This would be performing a query on each element of an array but in a single query. Is this possible or would I have to write a query for each room?

select   name,
         eventtime,
         MIN(eventtime - currenttime) as time_from_test
from     the_table
where    the_table.room = Room1
group by the_table.room
order by time_from_test
limit 1

Thanks in advance

Answer 1

select   the_table.room,MIN(eventtime) as event_start_time_of_day
from     the_table
group by the_table.room;

For eg. if you have 5 rooms and each room has five event times then this query will retrieve the minimum event time and return it back to you by grouping all events at room level.