Question

Can anyone offer suggestions for the logic in a MySQL query that does the following:

• Selects at least 100 posts
• Selects all of the posts in the last month of loaded thoughts, e.g., if 100 posts loads posts half way through September, then the posts for the entire month of September should be loaded instead of cutting it off half way.

Unfortunately, the second option is not something I know is even possible with MySQL, so I’m reaching out for a little help.

Cheers.

Answer 1

just compute the month of the 100th row in a subquery and use the value in BETWEEN condition

What you basically need:

• find the date of the 100th row (date_a)
• find the first day of the month of the date_a (date_b)
• find all rows that are newer than the date_b

Thus,

SELECT created as date_a
FROM posts
ORDER BY created DESC
LIMIT 99, 1

SELECT
  (LAST_DAY(created) + INTERVAL 1 DAY - INTERVAL 1 MONTH) as date_b
FROM posts
ORDER BY created DESC
LIMIT 99, 1

The last query where the latter is used as subquery is your homework =)