MySQL convert column datatype from VARCHAR to INT

Question

I have a MySQL table with a VARCHAR(25) column that I want to convert to INT. All of the data in the column is either integer or blanks. I have tried this command:

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Answer 1

before altering your table, try to update your values.

The goal is to set a '0' value in the fields where you have empty values (which can't be converted to int)

update ip
set isp = '0' where trim(coalesce(isp, '')) = '';

If isp was not nullable, you can remove the coalesce function.

update ip 
set isp = '0' where trim(isp) = '';