LENGTH function

LENGTH returns the code points in an encoded string.

Signatures

Return value

length returns an int.

Details

Errors

length operations might return NULL values indicating errors in the following cases:

• The encoding_name provided is not available in our encoding package.
• Some byte sequence in str was not compatible with the selected encoding.

Fixed-width strings

Materialize returns the length of fixed-width strings as the maximum width of the string. For example length on a CHAR(15) column returns 15 as each string’s length.

Materialize receives strings from your database in the same format they are emitted. In the case of fixed-width strings, e.g. CHAR columns in PostgreSQL, we receive the value padded by empty spaces. Because we cannot determine whether those spaces were intentional or an artifact of a fixed-width string, we provide the length of the string as we received it.

You can find any updates on this behavior in this GitHub issue.

Encoding details

• Materialize uses the encoding crate. See the list of supported encodings, as well as their names within the API.

• Materialize attempts to convert PostgreSQL-style encoding names into the WHATWG-style encoding names used by the API.

  For example, you can refer to iso-8859-5 (WHATWG-style) as ISO_8859_5 (PostrgreSQL-style).

  However, there are some differences in the names of the same encodings that we do not convert. For example, the windows-874 encoding is referred to as WIN874 in PostgreSQL; Materialize does not convert these names.

Examples

SELECT length('你好') AS len;

 len
-----
   2

SELECT length('你好', 'big5') AS len;

 len
-----
   3