Functions
=========

Conversion Functions
--------------------

* ``CAST``

Temporal Functions
------------------

* ``to_string``
* ``to_timestamp``
* ``utcnow``
* ``date_add``
* ``date_diff``
* ``extract``

Pattern Matching Functions
--------------------------

* ``regexp_contains``

Aggregate Functions
-------------------

.. list-table::
   :header-rows: 1
   :widths: 28 24 30 18

   * - Function
     - Argument type
     - Return type
     - Description
   * - ``AVG(expression)``
     - ``INT``, ``FLOAT``, ``DECIMAL``
     - Decimal for integer input, float for floating point input, otherwise the argument type.
     - Average.
   * - ``COUNT(expression)`` or ``COUNT(*)``
     - Any row.
     - ``INT``
     - Count. Returns ``0`` for zero matched rows.
   * - ``MAX(expression)``
     - ``INT``, ``DECIMAL``
     - Same as the argument type.
     - Maximum.
   * - ``MIN(expression)``
     - ``INT``, ``DECIMAL``
     - Same as the argument type.
     - Minimum.
   * - ``SUM(expression)``
     - ``INT``, ``FLOAT``, ``DOUBLE``, ``DECIMAL``
     - Integer for integer input, float for floating point input, otherwise the argument type.
     - Sum.
   * - ``STDDEV_SAMP(expression)``
     - ``INT``, ``FLOAT``, ``DOUBLE``, ``DECIMAL``
     - Decimal for integer input, float for floating point input, otherwise the argument type.
     - Sample standard deviation.