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Task/Hash-join/LFE/hash-join-1.lfe

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+(defun hash (column table)
+  (lists:foldl
+    (lambda (x acc)
+      (orddict:append (proplists:get_value column x) x acc))
+    '()
+    table))
+
+(defun get-hash (col hash-table)
+  (proplists:get_value
+     (proplists:get_value col r)
+     hashed))
+
+(defun merge (row-1 row-2)
+  (orddict:merge
+    (lambda (k v1 v2) v2)
+    (lists:sort row-1)
+    (lists:sort row-2)))
+
+(defun hash-join (table-1 col-1 table-2 col-2)
+  (let ((hashed (hash col-1 table-1)))
+    (lc ((<- r table-2))
+        (lc ((<- s (get-hash col-2 hashed)))
+            (merge r s)))))