Question

I’m storing timestamp as int field. And on large table it takes too long to get rows inserted at date because I’m using mysql function FROM_UNIXTIME.

SELECT * FROM table WHERE FROM_UNIXTIME(timestamp_field, '%Y-%m-%d') = '2010-04-04'

Is there any ways to speed this query? Maybe I should use query for rows using timestamp_field >= x AND timestamp_field < y?

Thank you

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EDITED This query works great, but you should take care of index on timestamp_field.

SELECT * FROM table WHERE 
timestamp_field >= UNIX_TIMESTAMP('2010-04-14 00:00:00')
AND timestamp_field <= UNIX_TIMESTAMP('2010-04-14 23:59:59')

Answer 1

Use UNIX_TIMESTAMP on the constant instead of FROM_UNIXTIME on the column:

SELECT * FROM table
WHERE timestamp_field
   BETWEEN UNIX_TIMESTAMP('2010-04-14 00:00:00')
       AND UNIX_TIMESTAMP('2010-04-14 23:59:59')

This can be faster because it allows the database to use an index on the column timestamp_field, if one exists. It is not possible for the database to use the index when you use a non-sargable function like FROM_UNIXTIME on the column.

If you don’t have an index on timestamp_field then add one.

Once you have done this you can also try to further improve performance by selecting the columns you need instead of using SELECT *.