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DOC: Add doc-string examples for pd.read_sql using custom parse_dates arg values #38475

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Merged
merged 6 commits into from
Dec 17, 2020
Merged
35 changes: 35 additions & 0 deletions pandas/io/sql.py
Original file line number Diff line number Diff line change
Expand Up @@ -478,6 +478,41 @@ def read_sql(
-------
DataFrame or Iterator[DataFrame]

Examples
--------
Read data from SQL via either a SQL tablename or a SQL query

>>> pd.read_sql('table_name', 'postgres:///db_name') # doctest:+SKIP
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Maybe the examples can demonstrate connecting to a sqlite db so we don't have to skip all these doctests

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Done


>>> pd.read_sql('SELECT * FROM table_name', 'postgres:///db_name') # doctest:+SKIP

Apply dateparsing to columns through the "parse_dates" argument
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Double backticks around parse_dates instead

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Done


>>> pd.read_sql('table_name',
... 'postgres:///db_name',
... parse_dates=["date_column"]) # doctest:+SKIP

The "parse_dates" argument calls pd.to_datetime on the provided columns. Custom
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Double backticks around pd.to_datetime

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Done

argument values for applying pd.to_datetime on a column are specified via a
dictionary format:
1. Ignore errors while parsing the values of "date_column"

>>> pd.read_sql('table_name',
... 'postgres:///db_name',
... parse_dates={"date_column": {"errors": "ignore"}) # doctest:+SKIP

2. Apply a dayfirst dateparsing order on the values of "date_column"

>>> pd.read_sql('table_name',
... 'postgres:///db_name',
... parse_dates={"date_column": {"dayfirst": True}) # doctest:+SKIP

3. Apply custom formatting when dateparsing the values of "date_column"

>>> pd.read_sql('table_name',
... 'postgres:///db_name',
... parse_dates={"date_column": {"format": "%d/%m/%Y"}) # doctest:+SKIP

See Also
--------
read_sql_table : Read SQL database table into a DataFrame.
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