Question

Hello EVery I am new to SQl. query to result in the following records.

I have a table with records as

c1  c2            c3                  c4    c5   c6

1  John         2.3.2010 12:09:54     4     7    99        
2  mike         2.3.2010 13:09:59     8     6    88   
3  ahmad         2.3.2010 13:09:59     1     9    19   


4  Jim        23.3.2010 16:35:14      4     5    99   
5  run        23.3.2010 12:09:54      3     8    12 

I want to fecth only records.
i.e only 1 latest record per day. If both of them happen at the same time, sort by C1.so in 1&3 it should fetch 3.

3  ahmad         2.3.2010 14:09:59     1     9    19   
4  Jim        23.3.2010 16:35:14      4     5    99

I have got a new problem in this.
If i filter the records based on conditions the last record is missing. I tried many ways but still it is failing. Here update_log is my table.

SELECT * FROM update_log t1 
WHERE (t1.c3) = 
(
    SELECT MAX(t2.c3) 
    FROM update_log t2 
    WHERE DATEDIFF(dd,t2.c3, t1.c3) = 0 
)
and t1.c3 > '02.03.2010' and t1.modified_at <= '22.03.2010' 

ORDER BY t1.c3 ASC. But i am not able to retrieve the record

4  Jim        23.3.2010 16:35:14      4     5    99

I dont know this query results in only

  3  ahmad         2.3.2010 14:09:59     1     9    19   

The format of the column c3 is datetime. I am pumping the data into the column as
using $date = date("d.m.Y H:i",time()); — simple date fetch of today.

Another query that i tried for the same purpose.

select * from (select convert(varchar(10), c3,104) as date, max(c3) as max_date, max(c1) as Nr from update_log group by convert(varchar(10), c3,104)) as t2 inner join update_log as t1 on (t2.max_date = t1.c3 and convert(varchar(10), c3,104) = date and t1.[c1]= Nr) WHERE t1.c3 >= '02.03.2010' and t1.c3 <= '16.04.2010' . I even tried this way..the same error last record is not coming..

Answer 1

OK, Now i understood. actually i wrote the query for the same purpose this way.

select * from #temp 
select * from
(select max(c1) as nr from 
(select convert(varchar(10), c3,104) as date, max(c3) as max_date
 from #temp  where 
 convert(varchar(10),c3,104) >=  '02.02.2010' and 
convert(varchar(10),c3,104) <= '23.02.2010'
group by convert(varchar(10), c3,104))
 as t2 inner join #temp as t1 on (t2.max_date = t1.c3 and 
convert(varchar(10), c3,104) = date)  
group by convert(varchar(10),max_date,104))
as t3 inner join #temp as t4 on (t3.nr = t4.c1 )

If i change these 2 lines to c3 >= ‘02.02.2010’ and
c3 <= ‘24.02.2010’. It is working fine. but the query that i have posted is not able to filter the records properly based on dates.

I want to know where i went to wrong to enhance my knoweldge rather than just copying ur query:-)