RosettaCodeData/Task/Hash-join/J/hash-join-1.j

table1=: ;:;._2(0 :0)
  27 Jonah
  18 Alan
  28 Glory
  18 Popeye
  28 Alan
)

table2=: ;:;._2(0 :0)
  Jonah Whales
  Jonah Spiders
  Alan Ghosts
  Alan Zombies
  Glory Buffy
)