LENGTH(str)Returns the length of the string str.
In the default mode, when Oracle mode is not set, the length is measured in bytes. In this case, a multi-byte character counts as multiple bytes. This means that for a string containing five two-byte characters, LENGTH() returns 10, whereas CHAR_LENGTH() returns 5.
When running Oracle mode, the length is measured in characters, and LENGTH is a synonym for CHAR_LENGTH().
If str is not a string value, it is converted into a string. If str is NULL, the function returns NULL.
SELECT LENGTH('MariaDB');
+-------------------+
| LENGTH('MariaDB') |
+-------------------+
| 7 |
+-------------------+When Oracle mode is not set:
SELECT CHAR_LENGTH('π'), LENGTH('π'), LENGTHB('π'), OCTET_LENGTH('π');
+-------------------+--------------+---------------+--------------------+
| CHAR_LENGTH('π') | LENGTH('π') | LENGTHB('π') | OCTET_LENGTH('π') |
+-------------------+--------------+---------------+--------------------+
| 1 | 2 | 2 | 2 |
+-------------------+--------------+---------------+--------------------+In Oracle mode:
SELECT CHAR_LENGTH('π'), LENGTH('π'), LENGTHB('π'), OCTET_LENGTH('π');
+-------------------+--------------+---------------+--------------------+
| CHAR_LENGTH('π') | LENGTH('π') | LENGTHB('π') | OCTET_LENGTH('π') |
+-------------------+--------------+---------------+--------------------+
| 1 | 1 | 2 | 2 |
+-------------------+--------------+---------------+--------------------+This page is licensed: GPLv2, originally from fill_help_tables.sql