How can I create a temporary table in mariadb or mysql?

Now, I'm migrating mssql to mariadb(mysql). Mssql has with clause(with A as ()), but mysql has not with clause. So I'm using "create temporary table", but some error occurred.

Example,

CREATE TEMPORARY TABLE TMP(
    SELECT CAST(DATE_FORMAT(NOW(), '%Y-%m-%d %T.%f') AS CHAR(19)) AS REGDT
);

and this is error code

MySQL Database Error: Truncated incorrect CHAR(19) value: '2016-06-27 10:34:34.000000'

What is wrong?

This is my query.

CREATE TEMPORARY TABLE TMP(
  SELECT DEPTCODE, DEPTNAME, USEYN, HIGHDEPTCODE, 
         CAST(DATE_FORMAT(REGDT, '%Y-%m-%d %T.%f') AS CHAR(19)) AS REGDT,
         0 AS LEV, CAST(DEPTCODE AS CHAR(255)) AS SORT, DEPTORDER 
    FROM TBDEPARTMENT
   WHERE DEPTCODE = '1000');