Question

How to select last date in 2 records in Mysql ?

TABLE A

SID NAME Sex
1  Jam  M
2  Da   F

TABLE B

 ID Title SID Date
   1  A     1   2012-07-31 09:57:10
   2  NULL  1   2012-07-31 09:57:13
   3  A     2   2012-07-31 10:10:13
   4  NULL  2   2012-07-31 10:57:13

I want to inner join those two tables,

but select only one record only of Table B(distinct of SID) where title not null then show the

biggest Date of title is null field.

Result want the biggest Date of Null title:

ID Name Title SID  Date
1  Jam  A     1    **2012-07-31 09:57:13**
2  DA   A     2    **2012-07-31 10:57:13**

How to do that ?

Answer 1

SELECT b.ID, a.NAME, b.Title, b.SID, b.Datea 
from tablea a left outer join 
  (( SELECT sid, MAX(datea) AS latest
         FROM tableb
          where title is not null 
          GROUP BY sid) AS dt
INNER JOIN tableb b  ON b.sid= dt.sid  and b.datea=dt.latest )
on a.sid=b.sid