To insert data into a MySQL database while preserving the already existing data, you will just concatenate your new data to the end of your existing data.

Below is an example of how to do it using the column “changelog” which is used to keep track of changes made to the row/record.

UPDATE table1 SET changelog=CONCAT(changelog,"new data") WHERE id='idnumber'

If you would like the data that you are entering to appear at the beginning of the existing data, simply flip the concatenation, example:

UPDATE table1 SET changelog=CONCAT("new data",changelog) WHERE id='idnumber'