Join or merge function in haskell -

is there function in haskell equivalent of sql join or r merge ?

basically have 2 list of tuples , 'zip' them according key. know there 1 or 0 value each key

a = [(1, "hello"), (2, "world")] b = [(3, "foo"), (1, "bar")] 

and like

 [ (just (1, "hello), (1, "bar))  , (just (2, "world), nothing)  , (nothing         , (3, "foo"))  ] 

i can not think of standard function doing operation. convert 2 lists data.map.maps , code sql-join myself. in way, looks doable o(n log n) complexity, not bad.