kosiew commented on code in PR #1184:
URL:
https://github.com/apache/datafusion-python/pull/1184#discussion_r2506890128
##########
docs/source/user-guide/common-operations/joins.rst:
##########
@@ -101,4 +101,36 @@ the right table.
.. ipython:: python
- left.join(right, left_on="customer_id", right_on="id", how="anti")
\ No newline at end of file
+ left.join(right, left_on="customer_id", right_on="id", how="anti")
+
+Duplicate Keys
+--------------
+
+It is common to join two DataFrames on a common column name. Starting in
+version 51.0.0, ``datafusion-python``` will now drop duplicate column names by
+default. This reduces problems with ambiguous column selection after joins.
+You can disable this feature by setting the parameter ``drop_duplicate_keys``
+to ``False``.
+
+.. ipython:: python
+
+ left = ctx.from_pydict(
+ {
+ "id": [1, 2, 3],
+ "customer": ["Alice", "Bob", "Charlie"],
+ }
+ )
+
+ right = ctx.from_pylist([
+ {"id": 1, "name": "CityCabs"},
+ {"id": 2, "name": "MetroRide"},
+ {"id": 5, "name": "UrbanGo"},
+ ])
+
+ left.join(right, "id", how="inner")
+
+In contrast to the above example, if we wish to get both columns:
+
+.. ipython:: python
+
+ left.join(right, "id", "inner", drop_duplicate_keys=False)
Review Comment:
```suggestion
left.join(right, "id", how="inner", drop_duplicate_keys=False)
```
##########
docs/source/user-guide/common-operations/joins.rst:
##########
@@ -101,4 +101,36 @@ the right table.
.. ipython:: python
- left.join(right, left_on="customer_id", right_on="id", how="anti")
\ No newline at end of file
+ left.join(right, left_on="customer_id", right_on="id", how="anti")
+
+Duplicate Keys
+--------------
+
+It is common to join two DataFrames on a common column name. Starting in
+version 51.0.0, ``datafusion-python``` will now drop duplicate column names by
+default. This reduces problems with ambiguous column selection after joins.
+You can disable this feature by setting the parameter ``drop_duplicate_keys``
+to ``False``.
+
+.. ipython:: python
+
+ left = ctx.from_pydict(
+ {
+ "id": [1, 2, 3],
+ "customer": ["Alice", "Bob", "Charlie"],
+ }
+ )
+
+ right = ctx.from_pylist([
+ {"id": 1, "name": "CityCabs"},
+ {"id": 2, "name": "MetroRide"},
+ {"id": 5, "name": "UrbanGo"},
+ ])
+
+ left.join(right, "id", how="inner")
+
+In contrast to the above example, if we wish to get both columns:
+
+.. ipython:: python
+
+ left.join(right, "id", "inner", drop_duplicate_keys=False)
Review Comment:
to be consistent with line 130 above
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