How can I search/replace strings in MySQL?

MySQL lets you replace all occurrences of a character or string of characters in a table with some other character or string. 
 UPDATE table SET field1 = REPLACE(field1, 'replace_that', 'with_this'), field2 = REPLACE(field2, 'and_that', 'with_this') 
 As an example, let’s say that you have a pets table and you want to change every cat into a dog: 
 UPDATE pets SET species = REPLACE(species, 'cat', 'dog') 
 This feature is also useful for transposing characters from one encoding to another. Here’s how to change Windows-style CRLF line endings into Unix-style LF line endings: 
 UPDATE users SET bio = REPLACE(bio, CONCAT(CHAR(13), CHAR(10)), CHAR(10)) 
 Of course, you don’t have to replace all occurrences in a table if you don’t want to. Just supply a WHERE clause and only those rows will be affected.