+-------+--------------------+----+
|User-ID|            Location| Age|
+-------+--------------------+----+
|      1|  nyc, new york, usa|NULL|
|      2|stockton, califor...|  18|
|      3|moscow, yukon ter...|NULL|
|      4|porto, v.n.gaia, ...|  17|
|      5|farnborough, hant...|NULL|
|      6|santa monica, cal...|  61|
|      7| washington, dc, usa|NULL|
|      8|timmins, ontario,...|NULL|
|      9|germantown, tenne...|NULL|
|     10|albacete, wiscons...|  26|
|     11|melbourne, victor...|  14|
|     12|fort bragg, calif...|NULL|
|     13|barcelona, barcel...|  26|
|     14|mediapolis, iowa,...|NULL|
|     15|calgary, alberta,...|NULL|
|     16|albuquerque, new ...|NULL|
|     17|chesapeake, virgi...|NULL|
|     18|rio de janeiro, r...|  25|
|     19|           weston, ,|  14|
|     20|langhorne, pennsy...|  19|
+-------+--------------------+----+

+-------+----------+-----------+
|User-ID|      ISBN|Book-Rating|
+-------+----------+-----------+
| 276725|034545104X|          0|
| 276726|0155061224|          5|
| 276727|0446520802|          0|
| 276729|052165615X|          3|
| 276729|0521795028|          6|
| 276733|2080674722|          0|
| 276736|3257224281|          8|
| 276737|0600570967|          6|
| 276744|038550120X|          7|
| 276745| 342310538|         10|
| 276746|0425115801|          0|
| 276746|0449006522|          0|
| 276746|0553561618|          0|
| 276746|055356451X|          0|
| 276746|0786013990|          0|
| 276746|0786014512|          0|
| 276747|0060517794|          9|
| 276747|0451192001|          0|
| 276747|0609801279|          0|
| 276747|0671537458|          9|
+-------+----------+-----------+

def crearDataFrame(nombre_fichero):
    df = spark.read.format("csv").option("header", "true").option("delimiter", ";").load(nombre_fichero)
    return df

dfUser = crearDataFrame("BX-Users.csv")
dfBooks_Rating = crearDataFrame("BX-Book-Ratings.csv")

df_ = dfUser.join(dfBooks_Rating, dfUser.User-ID == dfBooks_Rating.User-ID, 'inner').show()