Changing Column in MySQL from int to double?

问题:

Basically, I currently have a column in a MySQL table, which is an int.

I'd like to change that to double. I've searched the web, but all it came up with was conversion upon getting the values from the column (like converting some date to Date), but that's not what I mean.

I'm guessing it's something with Alter Table, and I looked that up on the MySQL dev page, but could not find what I was looking for.

回答1:

Here's the real syntax. Make sure to set the nullability appropriately too:

ALTER TABLE your_table
MODIFY COLUMN your_column DOUBLE NULL;

or

ALTER TABLE your_table
MODIFY COLUMN your_column DOUBLE NOT NULL;

回答2:

You're right that you need to use ALTER TABLE. The command will look something like this:

ALTER TABLE tablename MODIFY COLUMN columnname DOUBLE;