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MySQL HeatWave User Guide  /  ...  /  Functions and Operator Limitations

2.16.3 Functions and Operator Limitations

  • Bit functions and operators.

  • CAST() AS SIGNED and UNSIGNED on temporal values.

    For supported CAST() operations, see Section 2.12.3, “Cast Functions and Operators”.

  • COALESCE() as a JOIN predicate.

  • CONVERT_TZ() with named time zones such as MET or Europe/Amsterdam.

    Only datetime values are supported. Rewrite queries that use named time zones with equivalent datetime values. For example:

    mysql> SELECT CONVERT_TZ(O_ORDERDATE, 'UTC','EST') FROM tpch.orders

    Rewrite as:

    mysql> SELECT CONVERT_TZ(O_ORDERDATE, '+00:00','-05:00') FROM tpch.orders
  • Full-text search functions.

  • XML, JSON, Spatial, and other domain specific functions.

  • Loadable Functions.

  • GROUP_CONCAT() with:

    GROUP_CONCAT() is only supported in strict mode.

  • GREATEST() and LEAST() functions with the YEAR type.

    GREATEST() and LEAST() do not support comparison between temporal and non-temporal types.

    DATE, DATETIME, TIME, and TIMESTAMP support was added in MySQL 8.0.30.

  • A CASE control flow operator or IF() function that contains columns not within an aggregation function and not part of the GROUP BY key.

  • Date functions on the YEAR type.

  • String functions and operators on columns that are not VARLEN-encoded. See Section 2.7.1, “Encoding String Columns”.

  • In some cases, comparison functions with a mixture of string and non-string arguments due to HeatWave returning incorrect results.

  • The AVG() aggregate function with enumeration and temporal data types.

  • The following aggregate functions with enumeration, string, and temporal data types:

    With the exception of SUM(), the same aggregate functions within a semi-join predicate due to the nondeterministic nature of floating-point results and potential mismatches. For example, the following use is not supported:

    mysql> SELECT FROM A WHERE a1 IN (SELECT VAR_POP(b1) FROM B);

    The same aggregate functions with numeric data types other than those supported by HeatWave. See Section 2.10, “Supported Data Types”.

  • WEEK(date[,mode]) does not support the default_week_format system variable.

    To use the mode argument, the mode value must be defined explicitly.