13.3.5 The VECTOR Type

A VECTOR is a structure that can hold up to a specified number of entries N, defined as shown here:

VECTOR(N)

Each entry is a 4-byte (single-precision) floating-point value.

The default length is 2048; the maximum is 16383 entries. To declare a VECTOR column of the default length, define it as VECTOR with no parentheses following; trying to define a column as VECTOR() (with empty parentheses) raises a syntax error.

A VECTOR cannot be compared to any other type. It can be compared to another VECTOR for equality, but no other comparison is possible.

A VECTOR column cannot be used as any type of key. This includes all of the following types:

• Primary key

• Foreign key

• Unique key

• Partitioning key

A VECTOR column also cannot be used as a histogram source.

VECTOR Supported and Unsupported Functions

VECTOR values can be used with the MySQL string functions BIT_LENGTH(), CHAR_LENGTH(), HEX(), LENGTH(), and TO_BASE64(). Other string functions do not accept the VECTOR type as an argument.

VECTOR can be used as an argument to any of the encryption functions AES_ENCRYPT(), COMPRESS(), MD5(), SHA1(), and SHA2(). VECTOR is not supported as an argument type by any other encryption functions.

VECTOR can be used as an argument to the CASE operator and related flow-control functions, including COALESCE(), IFNULL(), NULLIF(), and IF().

VECTOR can be used as the argument to CAST(expression AS BINARY); the result is a binary string with the same contents as the VECTOR argument. Casting to VECTOR with CAST is not supported; you can convert a suitable string to VECTOR using STRING_TO_VECTOR().

VECTOR data types cannot be used as arguments to aggregate functions or window functions other than COUNT [DISTINCT].

VECTOR cannot be used as an argument to any of the following types of functions and operators:

• Numeric functions and operators

• Temporal functions

• Fulltext search functions

• XML functions

• Bit functions such as bitwise AND and OR

• JSON functions

For more information, see Section 14.21, “Vector Functions”.

VECTOR values are supported by JavaScript stored programs in MySQL 9.1 and later. See Section 27.3.4, “JavaScript Stored Program Data Types and Argument Handling”, for more information.