oracle db how to get unique item per user

[sasori]

Hi, I have a problem whereby I need to produce "only" one item per user e.g

it's a portal that has many users and they can post alot of items, regardless whether it's a registered or non registered user.

can someone give me a pseudo thing that may help solve this sql statement problem?

or atleast an sql code snippet..

 

if I do this

 

select userid, itemtitle, max(itemid) as ad from itemtable where status = 1
and expirydate > current_date and publishdate is not null and displaypublishdate is not null 
group by userid order by displaypublishdate desc;

it throws an error in my sql developer

 

 

ORA-00979: not a GROUP BY expression
00979. 00000 -  "not a GROUP BY expression"
*Cause:    
*Action:
Error at Line: 33 Column: 15

it only produces results when i changed the "order by" into 

order by ad 

and removed the itemtitle among the selected columns

 

but I need to order it by displayplublishdate or publishdate in descending order..and also

I need to get the item title as well...because I need to display the item title in the front-end of the portal

 

so how?