Server!/Horror! I have a magnet and I don't mind using it!

When can a TINYTEXT column have a default value?

This:

$ mysql -u root test
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2496
Server version: 5.0.51a-3ubuntu5.4-log (Ubuntu)
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> create table t1 (a tinytext default 'fail');
ERROR 1101 (42000): BLOB/TEXT column 'a' can't have a default value
mysql> create table t1 (a tinytext default '');
Query OK, 0 rows affected, 1 warning (0.07 sec)
mysql> show warnings;
+---------+------+-------------------------------------------------+
| Level   | Code | Message                                         |
+---------+------+-------------------------------------------------+
| Warning | 1101 | BLOB/TEXT column 'a' can't have a default value |
+---------+------+-------------------------------------------------+
1 row in set (0.00 sec)

wouldn’t have happened with a real database:

create TABLE xxxx(
 id serial,
 bla text default 'foo'
);
-- NOTICE:  CREATE TABLE will create implicit sequence "xxxx_id_seq" for serial column "xxxx.id"
CREATE TABLE
test=# INSERT into xxxx (id) values (1);
INSERT 0 1
test=# SELECT * from xxxx;
 id | bla
----+-----
  1 | foo
(1 row)

Generated: 2017-11-02 10:20:47 +0100