Update README.md [ci skip]

Author: olekscode

README.md

@@ -292,3 +292,16 @@ If you rather want to select all the columns of a data frame, use the `selectAll
 df selectAllWhere: [ :species :sepal_width |
    species = #setosa and: sepal_width = 3 ].
 ```
+
+This query will return a data frame will all 5 columns of Iris dataset and 6 rows that satisfy the given condition.
+
+```smalltalk
+    |  sepal_length  sepal_width  petal_length  petal_width  species  
+----+---------------------------------------------------------------
+ 2  |           4.9            3           1.4          0.2  setosa   
+13  |           4.8            3           1.4          0.1  setosa   
+14  |           4.3            3           1.1          0.1  setosa   
+26  |             5            3           1.6          0.2  setosa   
+39  |           4.4            3           1.3          0.2  setosa   
+46  |           4.8            3           1.4          0.3  setosa
+```