below is the test table created. As data type is set to varchar it shouldn’t accept int values.

desc c\G
*************************** 1. row ***************************

  Field: t
   Type: int(6)
   Null: NO
Default: NULL

*************************** 2. row ***************************

  Field: h
   Type: varchar(5)
   Null: NO
Default: NULL

*************************** 3. row ***************************

  Field: e
   Type: varchar(6)
   Null: NO
Default: 0

MariaDB [test1]> insert into c values  (3,098765,654365);
Query OK, 1 row affected (0.00 sec).

My question is how to ask mariadb/mysql to prompt for error or stopped accepting the int values in varchar datatype.I already have strict mode set to

  • The strict mode "turns warnings to errors" - there is no warning for the implicit int->varchar conversion so there can be no error. MySQL statements just aren't strongly enough typed to check for that.
    – jkavalik
    Commented May 11, 2016 at 7:32
  • Not a bug. Some things should be done in application code, not the database.
    – Rick James
    Commented May 24, 2016 at 22:26

1 Answer 1


Your question relates to implicit type conversions.

I searched the MariaDB documentation but their description is not very detailed except to show examples of this happening (see https://mariadb.com/kb/en/mariadb/type-conversion/). MySQL has a similar page which definitively states it implicitly converts to/from strings as required (see http://dev.mysql.com/doc/refman/5.7/en/type-conversion.html).

For example, MySQL automatically converts numbers to strings as necessary, and vice versa.

The ISO-92 standard allows for implicit conversions but doesn't define all of them, it's vendor specific. However you can't stop this happening in SQL Server, or Oracle, I suspect it's by convention and can't be avoided.

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