MySQL - Replace Character in Columns

Just running the SELECT statement will have no effect on the data. You have to use an UPDATE statement with the REPLACE to make the change occur:

UPDATE photos
   SET caption = REPLACE(caption,'"','\'')

Here is a working sample: http://sqlize.com/7FjtEyeLAh

Replace below characters

~ ! @ # $ % ^ & * ( ) _ +
` - = 
{ } |
[ ] \
: " 
; '

< > ?
, . 

with this SQL

SELECT note as note_original, 

    REPLACE(
        REPLACE(
            REPLACE(
                REPLACE(
                    REPLACE(
                        REPLACE(
                            REPLACE(
                                REPLACE(
                                    REPLACE(
                                        REPLACE(
                                            REPLACE(
                                                REPLACE(
                                                    REPLACE(
                                                        REPLACE(
                                                            REPLACE(
                                                                REPLACE(
                                                                    REPLACE(
                                                                        REPLACE(
                                                                            REPLACE(
                                                                                REPLACE(
                                                                                    REPLACE(
                                                                                        REPLACE(
                                                                                            REPLACE(
                                                                                                REPLACE(
                                                                                                    REPLACE(
                                                                                                        REPLACE(
                                                                    REPLACE(
                                                                        REPLACE(
                                                                            REPLACE(
                                                                                REPLACE(
                                                                                    REPLACE(
                                                                                        REPLACE(
                                                                                            REPLACE(note, '\"', ''),
                                                                                        '.', ''),
                                                                                    '?', ''),
                                                                                '`', ''),
                                                                            '<', ''),
                                                                        '=', ''),
                                                                    '{', ''),
                                                                                                        '}', ''),
                                                                                                    '[', ''),
                                                                                                ']', ''),
                                                                                            '|', ''),
                                                                                        '\'', ''),
                                                                                    ':', ''),
                                                                                ';', ''),
                                                                            '~', ''),
                                                                        '!', ''),
                                                                    '@', ''),
                                                                '#', ''),
                                                            '$', ''),
                                                        '%', ''),
                                                    '^', ''),
                                                '&', ''),
                                            '*', ''),
                                        '_', ''),
                                    '+', ''),
                                ',', ''),
                            '/', ''),
                        '(', ''),
                    ')', ''),
                '-', ''),
            '>', ''),
        ' ', '-'),
    '--', '-') as note_changed FROM invheader

maybe I'd go by this.

 SQL = SELECT REPLACE(myColumn, '""', '\'') FROM myTable

I used singlequotes because that's the one that registers string expressions in MySQL, or so I believe.

Hope that helps.