2.18.2 Data Type Limitations

• Spatial data types. See Spatial Data Types.

• String and text data types::

  • BINARY

  • VARBINARY

• Decimal values with a precision greater than 18 in expression operators, with the exception of the following:

  • Arithmetic operators, see: Section 2.12.2, “Arithmetic Operators”.

  • CAST()

  • COALESCE()

  • CASE

  • IF()

  • NULLIF()

  • ABS()

  • CEILING()

  • FLOOR()

  • ROUND()

  • TRUNCATE()

  • GREATEST()

  • LEAST()

• ENUM type columns as part of a UNION, EXCEPT, EXCEPT ALL, INTERSECT, or INTERSECT ALL SELECT list or as a JOIN key, except when used inside a supported expression.

• ENUM type columns as part of a non-top level UNION ALL SELECT list or as a JOIN key, except when used inside a supported expression.

• ENUM type support is limited to:

  • Comparison with string or numeric constants, and other numeric, non-temporal expressions (numeric columns, constants, and functions with a numeric result).

  • Comparison operators (<, <=, <=>, =, >=, >, and BETWEEN) with numeric arguments.

  • Comparison operators (=, <=>, and <>) with string constants.

  • enum_col IS [NOT] {NULL|TRUE|FALSE}

  • The IN() function in combination with numeric arguments (constants, functions, or columns) and string constants.

  • COUNT(), SUM(), and AVG() aggregation functions on ENUM columns. The functions operate on the numeric index value, not the associated string value.

  • CAST(enum_col AS {[N]CHAR [(X)]|SIGNED|UNSIGNED|FLOAT|DOUBLE|DECIMAL [(M,N)]}). The numeric index value is cast, not the associated string value.

  • CAST(enum_col) AS {[N]CHAR} is supported only in the SELECT list and when it is not nested in another expression.

• Temporal types are supported only with strict SQL mode. See Strict SQL Mode.