Question

How do I modify this MySQL query to only count leadIDs from table leads where column ‘Date’ contains the newest (youngest) date?

SELECT COUNT(leadID) as accepted FROM leads WHERE change like '%OK%'

The problem is that leadID can have multiple instances in table leads. The original query result is “4” because of one duplicate. The correct result is “3”.

The date is stored in this format: 2011-10-26 18:23:52. The result should take hours and minutes into consideration when determining the youngest date.

TABLE leads:

leadID | date                | change
1      | 2011-10-26 18:23:52 | BAD
1      | 2011-10-26 17:00:00 | OK
2      | 2011-10-26 19:23:52 | OK
3      | 2011-10-26 20:23:52 | OK
4      | 2011-10-26 21:23:52 | OK
5      | 2011-10-26 22:23:52 | BAD 

Answer 1

I think this is what you’re looking for:

select count(distinct l1.leadId) as accepted from leads l1
left join leads l2
on l1.leadId = l2.leadId and l1.date < l2.date
where l2.date is null and l1.`change` like '%OK%'