MySQL - How to increase varchar size of an existing column in a database without breaking existing data?

Question

I have a column that is currently varchar(100) and I want to make it 10000.

is it as simple as

alter table table_name set          


        

Answer 1

For me this has worked-

ALTER TABLE table_name ALTER COLUMN column_name VARCHAR(50)

Answer 2

use this syntax: alter table table_name modify column col_name varchar (10000);

Answer 3

I'd like explain the different alter table syntaxes - See the MySQL documentation

For adding/removing defaults on a column:

ALTER TABLE table_name
ALTER COLUMN col_name {SET DEFAULT literal | DROP DEFAULT}

For renaming a column, changing it's data type and optionally changing the column order:

ALTER TABLE table_name
CHANGE [COLUMN] old_col_name new_col_name column_definition
[FIRST|AFTER col_name]

For changing a column's data type and optionally changing the column order:

ALTER TABLE table_name
MODIFY [COLUMN] col_name column_definition
[FIRST | AFTER col_name]

Answer 4

For me worked this one:

ALTER TABLE tablename MODIFY fieldname VARCHAR(128) NOT NULL;

Answer 5

I am using mysql and below syntax worked well for me,

ALTER TABLE table_name MODIFY col_name VARCHAR(12);

Answer 6

I normally use this statement:

ALTER TABLE `table_name`
  CHANGE COLUMN `col_name` `col_name` VARCHAR(10000);

But, I think SET will work too, never have tried it. :)