BUG: sql int column with null should result in f8 dtype

Author: wesm

pandas/io/tests/test_parsers.py

@@ -241,6 +241,11 @@ def test_convert_sql_column_ints(self):
         assert_same_values_and_dtype(result, expected)
         assert_same_values_and_dtype(result2, expected)
 
+        arr = np.array([1, 2, 3, None, 4], dtype='O')
+        result = lib.convert_sql_column(arr)
+        expected = np.array([1, 2, 3, np.nan, 4], dtype='f8')
+        assert_same_values_and_dtype(result, expected)
+
     def test_convert_sql_column_bools(self):
         arr = np.array([True, False, True, False], dtype='O')
         result = lib.convert_sql_column(arr)

pandas/src/parsing.pyx

@@ -135,14 +135,15 @@ def convert_sql_column(ndarray[object] objects):
             floats[i] = val
             seen_float = 1
         elif not (cpython.PyString_Check(val) or cpython.PyUnicode_Check(val)):
+            # this will convert Decimal objects
             try:
                 floats[i] = float(val)
                 seen_float = 1
             except Exception:
                 pass
 
     if seen_null:
-        if seen_float:
+        if seen_float or seen_int:
             return floats
         else:
             return objects