Getting the most recent entry per group in a select statement

Question

I have 3 tables to join to get table1.code, table1.series, table2.entry_date, table3.title1 and I'm trying to get the most recent non null table3.title1 grouped by table1.code and table1.series.

select table1.code, table1.series, max(table2.entry_date), table3.Title1 
                from table3 INNER JOIN table2 ON  table3.ID = table2.ID
                INNER JOIN table1 ON table2.source_code = table1.code
                where table3.Title1 is not NULL 
                group by table1.code, table1.series, table3.Title1

seems to give me all entries with a non null title1 instead of the most recent one. How should I structure the query to just pick the newest version of Title1 per code & series?

Answer 1

Try this:

select table1.code, table1.series, max(table2.entry_date), max(table3.Title1) as Title1
from table3 
INNER JOIN table2 ON  table3.ID = table2.ID
INNER JOIN table1 ON table2.source_code = table1.code
where table3.Title1 is not NULL 
And Table2.entry_Date = (Select Max(sq.entry_Date)
                        From sq.table2
                        Where sq.id = table2.ID)
group by table1.code, table1.series