MySQL Truncation Error - mysql

Question

In one of my tables, I have a column with some null values and some integer values. When I use MySQL Workbench to set a default value and non-null for that column, I get a truncation error.
When my colleague performs the same operation, his apply works and the null value are set to 0.
The only obvious difference is that he is running MySQL Server 5.6 and I am running 5.5.
An example table can be created with the following CREATE:
CREATE TABLE 'resource`.`test_table` (
`idtest_table` INT NOT NULL ,
`bad_column` BIGINT(20) NULL ,
PRIMARY KEY (`idtest_table`) );
Insert some values as follows:
INSERT INTO `resource`.`test_table` (`idtest_table`) VALUES (1);
INSERT INTO `resource`.`test_table` (`idtest_table`) VALUES (2);
INSERT INTO `resource`.`test_table` (`idtest_table`) VALUES (3);
The command that is failing is:
ALTER TABLE `resource`.`test_table` CHANGE COLUMN `bad_column` `bad_column` BIGINT(20) NOT NULL DEFAULT 0 ;
with the following error:
ERROR 1265: Data truncated for column 'bad_column' at row 1
SQL Statement:
ALTER TABLE `resource`.`test_table` CHANGE COLUMN `bad_column` `bad_column` BIGINT(20) NOT NULL DEFAULT 0
ERROR: Error when running failback script. Details follow.
ERROR 1050: Table 'test_table' already exists
SQL Statement:
CREATE TABLE `test_table` (
`idtest_table` int(11) NOT NULL,
`bad_column` bigint(20) DEFAULT NULL,
PRIMARY KEY (`idtest_table`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
Is there a setting in the MySQL config that allows this? Is it the version?

Answer 1

The error is occurring because bad_columns has a value of NULL after the insert.
You are changing the column type to "not NULL", so what can the database do? It can generate an error. The default value doesn't apply to existing rows.
If you want to do this, then update the column first:
update resource.test_table
set bad_column = 0
where bad_column is null;