MySQL appends a string to a field in the table:

MySQL appends a string to a field in the table:
UPDATE table_name set FIELD=CONCAT (field, ', str)

MySQL adds a string to a field in the table
UPDATE table_name set FIELD=CONCAT (' str ', field)

concat function in MySQL
How to use:
CONCAT (STR1,STR2,...)

Returns the string that results from the connection parameter. If any one of the arguments is NULL, the return value is null.

Attention:
If all parameters are non-binary strings, the result is a non-binary string.
If the argument contains any twos binary string, the result is a binary string.
A numeric parameter is converted to an equal binary string format; To avoid this, you can use explicit type cast, for example:
SELECT CONCAT (CAST (Int_col as CHAR), Char_col)