Show only most recent date from joined MySQL table

Question

I have 2 tables, a \"document\" table and a \"content\" table. They look like this (simplified):

document table:
docID
docTitle

content table:
contentID
doc         


        

Answer 1

try this:

select d.id, d.docTitle, MAX(c.dateAdd)
from document_table d
left join content_table c
on d.id = c.docId
group by d.id

Here is the thinking behind it: suppose document table has record A related to content(1, 2, 3, 4) and B related to (5, 6, 7, 8)

document        content

A               1
            2
                    3
            4

B               5
            6
            7
            8

a inner join with max(dateadded) will give you

document        content     max(dateadded)

A               1           1-1-2009...

A               2           1-1-2009...

A               3           1-1-2009...

A               4           1-1-2009...

B               5           2-1-2009...

B               6           2-1-2009...

B               7           2-1-2009...

B               8           2-1-2009...

after group by document id you will get

document    content     max(dateadded)

A           1           1-1-2009...

B           5           2-1-2009...

note: content id does not necessary match the id of the max dateadded