replace all occurrences of string in sql server code example

Example 1: sql replace character in string in all records

UPDATE employees 
SET 
    phone_number = REPLACE(phone_number, '.', '-');

Example 2: stuff and replace in sql

STUFF Function: This function is used to
overwrite existing character or inserts
a string into another string. 

REPLACE function: This function is used 
to replace the existing characters
of all the occurrences.