LENGTH function

LENGTH returns the code points in an encoded string.


length ( str , encoding_name )
Parameter Type Description
str string or bytea The string whose length you want.
encoding_name string The encoding you want to use for calculating the string’s length. Defaults to UTF-8.

Return value

length returns an int.



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


SELECT length('你好') AS len;

SELECT length('你好', 'big5') AS len;
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