How to attach concrete to wood?
With out any design sketch, a good way to bond wood to concrete is using threaded anchors  or threaded inserts

The difficult part is placing these inside the concrete column, to be level and not get dirty from concrete.



So using a fairly large size, so its easier to clean later, and easier to screw into.

Basically you would then insert a metal shaft in the wooden part and use a long screw that goes throught the wooden shaft freely but its head will clam the shaft.. and when you screw it into the concrete threaded anchor you essentially pull the wood tightly to the concrete pillar..

I could not find a diagram that illustrates this but this picture depicts the concept



So imagine the top of the screw, the part of your wooden table.. and the bottom part the concrete pillar, but using the threaded insert, instead of that bolt in the picture.

I have seen this used in building public park benches, with wooden planks fastened to concrete pillars... it is highly durable and very vandal proof.

But you might consider putting in three studs per column.. Three, in a triangle shape.. as this helps stabilize heavy objects. Or four in a SQUARE shape.. Using 1 you will need some sort of cross member or brace.. 2 is almost useless as you still need cross members or braces.