How to get size of column in mysql table

If you want to find out the size of column=COLUMN_NAME from table=TABLE_NAME, you can always run a query like this:

SELECT sum(char_length(COLUMN_NAME)) 
FROM TABLE_NAME;

Size returned is in bytes. If you want it in kb, you could just divide it by 1024, like so:

SELECT sum(char_length(COLUMN_NAME))/1024 
FROM TABLE_NAME;