You would flank, but cannot make Attacks of Opportunity*

Threatening


  Threatened Squares: You threaten all squares into which you can make a
  melee attack, even when it is not your turn. Generally, that means
  everything in all squares adjacent to your space (including
  diagonally). An enemy that takes certain actions while in a threatened
  square provokes an attack of opportunity from you. If you're unarmed,
  you don't normally threaten any squares and thus can't make attacks of
  opportunity.


AoO Rule:


  Cover and Attacks of Opportunity: You can't execute an attack of
  opportunity against an opponent with cover relative to you.


Soft Cover Rule:


  Soft Cover: Creatures, even your enemies, can provide you with cover
  against ranged attacks, giving you a +4 bonus to AC. However, such
  soft cover provides no bonus on Reflex saves, nor does soft cover
  allow you to make a Stealth check.


Those both come from the PRD section on Combat

As @Jim Kiley notes, there is no rule that states cover negates threatening. Just that it negates taking AoOs.

So, yes, the creature would provide a flanking bonus, but would be unable to make attacks of opportunity.

*This is muddied a bit by the fact that "Threatened Squares" are only described under attacks of opportunity, and it is a bit unclear if "threaten" == "can make an AoO". RAW, they're not technically the same thing, and thus my interpretation.

Edit: Turns out Creatures are only cover against ranged attacks, (double edit) but you determine cover as if with range if the target is not adjacent.


  When making a melee attack against a target that isn't adjacent to you
  (such as with a reach weapon), use the rules for determining cover
  from ranged attacks.


BUT

If the creature is large or larger, it gets to do this (which means if it's hampered by a medium creature it could probably finagle itself outside of cover):


  Big Creatures and Cover: Any creature with a space larger than 5 feet
  (1 square) determines cover against melee attacks slightly differently
  than smaller creatures do. Such a creature can choose any square that
  it occupies to determine if an opponent has cover against its melee
  attacks. Similarly, when making a melee attack against such a
  creature, you can pick any of the squares it occupies to determine if
  it has cover against you.


Does reach let you threaten an opponent if there is another opponent between you?
VALUES TRIM(CAST(CAST(YEAR( { fn  TIMESTAMPADD(SQL_TSI_MONTH,  -6  ,  
        CURRENT_DATE) }) AS CHAR(4) ) AS VARCHAR(4)))  || '-' ||     
        TRIM(CAST(CAST(MONTH( { fn  TIMESTAMPADD(SQL_TSI_MONTH, -6  ,   
          CURRENT_DATE) }) AS CHAR(2) ) AS VARCHAR(2))) 


The above statement returns 5 instead of 05 for MONTH(xxx)
which is not desired. It is not correct for comparisons
as 11 is smaller than 5 where in essense 11 is actually bigger
than 5

Edit:
With the JavaDB/Derby SQL statement above, I'd like to get
for example today is 2013-11-23, six months before was 2013-05-23
When comparing 

select p.ProductCode , p.ProductName as pn, sum( od.NetSales) AS Sales      
 from   
  products p   

  INNER JOIN order_details od ON (p.ProductCode = od.ProductCode)  
  INNER JOIN orders o ON (od.OrderCode = o.OrderCode)   
  where   TRIM(CAST(CAST(YEAR(o.PurchaseDateTime) AS CHAR(4)) AS VARCHAR(4))) || '-' ||    
  TRIM(CAST(CAST(MONTH(o.PurchaseDateTime)  AS CHAR(2)) AS VARCHAR(2)))      
              &gt;

  TRIM(CAST(CAST(YEAR( { fn  TIMESTAMPADD(SQL_TSI_MONTH,  -6   ,   CURRENT_DATE) }) AS CHAR(4) ) AS VARCHAR(4)))  || '-' ||    
  TRIM(CAST(CAST(MONTH( { fn  TIMESTAMPADD(SQL_TSI_MONTH, -6  ,   CURRENT_DATE) }) AS CHAR(2) ) AS VARCHAR(2)))         

       group by p.ProductCode, p.PRODUCTNAME


orders that are within the range are not included.
Whereas I want to include them
Hope you understand

Thanks
Jack
