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viirya · viirya · commit 4309001b0ff4 · 2016-04-12T01:44:42.000Z
diff --git a/python/pyspark/sql/dataframe.py b/python/pyspark/sql/dataframe.py
@@ -1199,6 +1199,9 @@ def approxQuantile(self, cols, probabilities, relativeError):
         if isinstance(cols, tuple):
             cols = list(cols)
         if isinstance(cols, list):
+            for c in cols:
+                if not isinstance(c, str):
+                    raise ValueError("column name should be string.")
             cols = _to_list(self._sc, cols)
 
         if not isinstance(probabilities, (list, tuple)):
