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===
SQL
===

Execute SQL SELECT queries against DataFrames and DataFrame UDFs.

Example::

    >>> import pyflink.dataframe as pf
    >>> df1 = pf.from_dict({"a": [1, 2, 3], "b": ["x", "y", "z"]})
    >>> df2 = pf.from_dict({"a": [1, 2, 3], "c": ["p", "q", "r"]})
    >>> joined = pf.sql("SELECT df1.a, b, c FROM df1 JOIN df2 ON df1.a = df2.a")
    >>> result = pf.sql(
    ...     "SELECT * FROM src WHERE a > 1",
    ...     auto_bind=False,
    ...     src=df1,
    ... )
    >>> @pf.udf
    ... def add_one(value: int) -> int:
    ...     return value + 1
    >>> pf.sql("SELECT add_one(a) AS a1 FROM df1")
    >>> pf.sql("SELECT inc(a) FROM src", auto_bind=False, src=df1, inc=add_one)
    >>> pf.sql("SELECT a, b FROM df1").filter(pf.col("a") > 1).to_pandas()

.. currentmodule:: pyflink.dataframe

.. autosummary::
    :toctree: api/

    sql