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Editorial Team
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Asked: 2026-06-10T03:42:11+00:00

Consider a table such as this: CREATE TABLE records ( id INT NOT NULL

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Consider a table such as this:

CREATE TABLE records (
    id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    eventOccured DATETIME NOT NULL,
    eventType INT NOT NULL,
    eventDescription VARCHAR(32)
)

I would like to retrieve the eventOccured and eventType fields from the entire table, but if two or more events occurred within an hour of each other then I would want only the first of them. This would be be simple if everything from N:00 to N:59 were considered the same hour, but in this case an event at 12:15 of eventType “5” would be considered to have occurred less than an hour after an 11:45 eventType “5”, and so should not be returned. Can this be done in MySQL without a stored procedure? I could write such a procedure, but I worry that it will be rather resource-intensive and I would love to learn if MySQL has such ability out of the box.

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1 Answer

  1. Editorial Team

    What you are saying is that you want all events, where there is not another event in the next 60 minutes. This query does this in what should be a mysql friendly way:

    select *
from records r
where not exists (select 1
                  from records r2
                  where r2.eventOccured > r.eventOccured and
                        timestampdiff(minute, r.eventOccured, r2.eventOccured) < 60
                 )
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