Querying Comma Delimited Values in MySQL

Question

I need a way to query a collection of data. I have a list of recent activity dates each stored in 1 row per user. Each row has a field of loginDates which consists of a comma separated list of timestamps.

What i need to do is run reports on this date to find people active since XXXXXX timestamp. The problem is the fact it's comma separated means i can't query it uses methods i know.

Here is an example row

id  userID  accessDates
2   6   1399494405,1399494465,1399494525,1399494585,1399494623

What i want to achieve in plain text

SELECT all_fields FROM accessTable WHERE accessDate > YESTERDAY 

ALSO These dates may however span over several hundreds of days with hundreds of timestamps in the field.

Answer 1

Assuming the TimeStamp values are in order as your data sample shows, if any of the TimeStamp values in the string are greater than a given date, then the latest one would be greater than that value as well. So you only need the latest TimeStamp value to meet your requirement:

SET @Yesterday =
  UNIX_TIMESTAMP(DATE_ADD(DATE(CURRENT_TIMESTAMP()),INTERVAL -1 DAY));

SELECT *
FROM accessTable
WHERE  CAST(RIGHT(accessDates,10) AS UNSIGNED) > @Yesterday;

If you want to query each of those TimeStamps individually, the best solution is to put them into a single table column with a userid:

userID    accessDate
------    ----------
6         1399494405
6         1399494465
6         1399494525
6         1399494585
6         1399494623