Function OCTET_LENGTH is not implemented but the documentation says yes.

[SunRunAway]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?
   If possible, provide a recipe for reproducing the error.

Function OCTET_LENGTH is not implemented but it is documented at https://pingcap.com/docs/dev/reference/sql/functions-and-operators/string-functions/

mysql> select OCTET_LENGTH(1);

2. What did you expect to see?

mysql> select OCTET_LENGTH(1);
+-----------------+
| OCTET_LENGTH(1) |
+-----------------+
|               1 |
+-----------------+
1 row in set (0.00 sec)

3. What did you see instead?

mysql> select OCTET_LENGTH(1);
ERROR 1305 (42000): FUNCTION octet_length does not exist

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

[gaoxingliang]

this issue seems not fixed yet on master branch. If so, I will look into this issue.