MySQL PHP alter table，将所有MEDIUMINT更改为INT

Question

In the past I've used a PHP script to change the language of all fields, but I can't find anything for switching all UNSIGNED MEDIUMINT to UNSIGNED INT. Is this possible? Should I manually switch them all? :o

Turns out mediumint is too small... so I have to change a lot of fields /:

edit: thanks for the input, I might just do it manually now that I know there's no simple automated way of doing it. I just didn't want to waste my time changing 100+ fields manually if there was an automated way.

Answer 1

MySQL does not have an automated way to say "take all of the columns of type X and change them to type Y." You may be able to query the information_schema database to figure out which columns you need to alter, and then you can build the ALTER TABLE query based on that information.

Specifically, have a look at the information_schema.columns table.

Answer 2

You can use the below query to find all mediumint columns (with respective table names) in a specific database and then iterate over the results to generate and execute ALTER queries in your choice of programming language.

SELECT 
    table_name, column_name, numeric_precision, column_type
FROM
    information_schema.columns
WHERE
    TABLE_SCHEMA = 'DATABASE_NAME'
        AND data_type = 'mediumint';

Answer 3

Has to be done in SQL, so if it makes sense in your case to write a script to do it, go for it, but most likely you will want to do it manually.

Since you are going from a data type that is less descriptive to a data type that is more descriptive, you should be fine.

Usint the ALTER TABLE Syntax should work:

ALTER TABLE table_name MODIFY column_name INT UNSIGNED