add colum,n to mysql table saving existing data code example

Example 1: create column mysql terminal

alter table icecream add column flavor varchar (20) ;

Example 2: Insert and initialize a SQL column with value dependent on another column data

UPDATE table
SET col = new_value
WHERE col = old_value
AND other_col = some_other_value;

UPDATE table
SET col = new_value
WHERE col = old_value
OR other_col = some_other_value;