{{tag>mariadb mysql troubleshooting}}

====== Mysql upgrade from Debian 9 to Debian 10 ======
You might get error like this

<code>
[ERROR] Incorrect definition of table mysql.event: expected column 'sql_mode' at position 14 to have type set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES','IGNORE_SPACE','IGNORE_BAD_TABLE_OPTIONS','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACTION','NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB','NO_KEY_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYSQL40','ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES','STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','INVALID_DATES','ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREATE_USER','HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_LENGTH'), found type set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES','IGNORE_SPACE','NOT_USED','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACTION','NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB','NO_KEY_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYSQL40','ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES','STRICT_A
2021-04-30  1:42:07 140285079196800 [ERROR] mysqld: Event Scheduler: An error occurred when initializing system tables. Disabling the Event Scheduler.

</code>

Fix by starting the database with ''--skip-grant-tables'' options

  mysqld --skip-grant-tables

Open new terminal window and run

  mysql_upgrade -u root -p

This should upgrade the tables and you can try starting the DB with ''systemctl'' command again.

However you might run into [[https://dw.exitstatus0.com/doku.php?id=wiki:mysql_mariadb_troubleshooting#mount_namespacing|this issue.]]

====== Tested on ======
  * Debian 9, 10

====== See also ======

====== References ======
  * https://www.digitalocean.com/community/questions/incorrect-definition-of-table-mysql-event-expected-column-sql_mode-at-position-14-to-have-type
  * https://bugs.mysql.com/bug.php?id=59364