Htykuut

No.

But if you have access to your server, you could use a user defined function (UDF) like mysql-udf-regexp.

EDIT: MySQL 8.0+ you could use natively REGEXP_REPLACE. More in answer above

Use MariaDB instead. It has a function

REGEXP_REPLACE(col, regexp, replace)

See MariaDB docs and PCRE Regular expression enhancements

Note that you can use regexp grouping as well (I found that very useful):

SELECT REGEXP_REPLACE("stackoverflow", "(stack)(over)(flow)", '\2 - \1 - \3')

returns

over - stack - flow

My brute force method to get this to work was just:

1. Dump the table - mysqldump -u user -p database table > dump.sql
   


2. Find and replace a couple patterns - find /path/to/dump.sql -type f -exec sed -i 's/old_string/new_string/g' {} ;, There are obviously other perl regeular expressions you could perform on the file as well.


3. Import the table - mysqlimport -u user -p database table < dump.sql
   

If you want to make sure the string isn't elsewhere in your dataset, run a few regular expressions to make sure they all occur in a similar environment. It's also not that tough to create a backup before you run a replace, in case you accidentally destroy something that loses depth of information.

I recently wrote a MySQL function to replace strings using regular expressions. You could find my post at the following location:

http://techras.wordpress.com/2011/06/02/regex-replace-for-mysql/

Here is the function code:

DELIMITER $$



CREATE FUNCTION  `regex_replace`(pattern VARCHAR(1000),replacement VARCHAR(1000),original VARCHAR(1000))

RETURNS VARCHAR(1000)

DETERMINISTIC

BEGIN 

 DECLARE temp VARCHAR(1000); 

 DECLARE ch VARCHAR(1); 

 DECLARE i INT;

 SET i = 1;

 SET temp = '';

 IF original REGEXP pattern THEN 

  loop_label: LOOP 

   IF i>CHAR_LENGTH(original) THEN

    LEAVE loop_label;  

   END IF;

   SET ch = SUBSTRING(original,i,1);

   IF NOT ch REGEXP pattern THEN

    SET temp = CONCAT(temp,ch);

   ELSE

    SET temp = CONCAT(temp,replacement);

   END IF;

   SET i=i+1;

  END LOOP;

 ELSE

  SET temp = original;

 END IF;

 RETURN temp;

END$$



DELIMITER ;

Example execution:

mysql> select regex_replace('[^a-zA-Z0-9-]','','2my test3_text-to. check \ my- sql (regular) ,expressions ._,');

we solve this problem without using regex
this query replace only exact match string.

update employee set

employee_firstname = 

trim(REPLACE(concat(" ",employee_firstname," "),' jay ',' abc '))

Example:

emp_id employee_firstname

1 jay

2 jay ajay

3 jay

After executing query result:

emp_id employee_firstname

1 abc

2 abc ajay

3 abc

I'm happy to report that since this question was asked, now there is a satisfactory answer! Take a look at this terrific package:

https://github.com/mysqludf/lib_mysqludf_preg

Sample SQL:

SELECT PREG_REPLACE('/(.*?)(fox)/' , 'dog' , 'the quick brown fox' ) AS demo;

I found the package from this blog post as linked on this question.

UPDATE 2: A useful set of regex functions including REGEXP_REPLACE have now been provided in MySQL 8.0. This renders reading on unnecessary unless you're constrained to using an earlier version.

UPDATE 1: Have now made this into a blog post: http://stevettt.blogspot.co.uk/2018/02/a-mysql-regular-expression-replace.html

The following expands upon the function provided by Rasika Godawatte but trawls through all necessary substrings rather than just testing single characters:

-- ------------------------------------------------------------------------------------

-- USAGE

-- ------------------------------------------------------------------------------------

-- SELECT reg_replace(<subject>,

--                    <pattern>,

--                    <replacement>,

--                    <greedy>,

--                    <minMatchLen>,

--                    <maxMatchLen>);

-- where:

-- <subject> is the string to look in for doing the replacements

-- <pattern> is the regular expression to match against

-- <replacement> is the replacement string

-- <greedy> is TRUE for greedy matching or FALSE for non-greedy matching

-- <minMatchLen> specifies the minimum match length

-- <maxMatchLen> specifies the maximum match length

-- (minMatchLen and maxMatchLen are used to improve efficiency but are

--  optional and can be set to 0 or NULL if not known/required)

-- Example:

-- SELECT reg_replace(txt, '^[Tt][^ ]* ', 'a', TRUE, 2, 0) FROM tbl;

DROP FUNCTION IF EXISTS reg_replace;

DELIMITER //

CREATE FUNCTION reg_replace(subject VARCHAR(21845), pattern VARCHAR(21845),

  replacement VARCHAR(21845), greedy BOOLEAN, minMatchLen INT, maxMatchLen INT)

RETURNS VARCHAR(21845) DETERMINISTIC BEGIN 

  DECLARE result, subStr, usePattern VARCHAR(21845); 

  DECLARE startPos, prevStartPos, startInc, len, lenInc INT;

  IF subject REGEXP pattern THEN

    SET result = '';

    -- Sanitize input parameter values

    SET minMatchLen = IF(minMatchLen < 1, 1, minMatchLen);

    SET maxMatchLen = IF(maxMatchLen < 1 OR maxMatchLen > CHAR_LENGTH(subject),

                         CHAR_LENGTH(subject), maxMatchLen);

    -- Set the pattern to use to match an entire string rather than part of a string

    SET usePattern = IF (LEFT(pattern, 1) = '^', pattern, CONCAT('^', pattern));

    SET usePattern = IF (RIGHT(pattern, 1) = '$', usePattern, CONCAT(usePattern, '$'));

    -- Set start position to 1 if pattern starts with ^ or doesn't end with $.

    IF LEFT(pattern, 1) = '^' OR RIGHT(pattern, 1) <> '$' THEN

      SET startPos = 1, startInc = 1;

    -- Otherwise (i.e. pattern ends with $ but doesn't start with ^): Set start pos

    -- to the min or max match length from the end (depending on "greedy" flag).

    ELSEIF greedy THEN

      SET startPos = CHAR_LENGTH(subject) - maxMatchLen + 1, startInc = 1;

    ELSE

      SET startPos = CHAR_LENGTH(subject) - minMatchLen + 1, startInc = -1;

    END IF;

    WHILE startPos >= 1 AND startPos <= CHAR_LENGTH(subject)

      AND startPos + minMatchLen - 1 <= CHAR_LENGTH(subject)

      AND !(LEFT(pattern, 1) = '^' AND startPos <> 1)

      AND !(RIGHT(pattern, 1) = '$'

            AND startPos + maxMatchLen - 1 < CHAR_LENGTH(subject)) DO

      -- Set start length to maximum if matching greedily or pattern ends with $.

      -- Otherwise set starting length to the minimum match length.

      IF greedy OR RIGHT(pattern, 1) = '$' THEN

        SET len = LEAST(CHAR_LENGTH(subject) - startPos + 1, maxMatchLen), lenInc = -1;

      ELSE

        SET len = minMatchLen, lenInc = 1;

      END IF;

      SET prevStartPos = startPos;

      lenLoop: WHILE len >= 1 AND len <= maxMatchLen

                 AND startPos + len - 1 <= CHAR_LENGTH(subject)

                 AND !(RIGHT(pattern, 1) = '$' 

                       AND startPos + len - 1 <> CHAR_LENGTH(subject)) DO

        SET subStr = SUBSTRING(subject, startPos, len);

        IF subStr REGEXP usePattern THEN

          SET result = IF(startInc = 1,

                          CONCAT(result, replacement), CONCAT(replacement, result));

          SET startPos = startPos + startInc * len;

          LEAVE lenLoop;

        END IF;

        SET len = len + lenInc;

      END WHILE;

      IF (startPos = prevStartPos) THEN

        SET result = IF(startInc = 1, CONCAT(result, SUBSTRING(subject, startPos, 1)),

                        CONCAT(SUBSTRING(subject, startPos, 1), result));

        SET startPos = startPos + startInc;

      END IF;

    END WHILE;

    IF startInc = 1 AND startPos <= CHAR_LENGTH(subject) THEN

      SET result = CONCAT(result, RIGHT(subject, CHAR_LENGTH(subject) + 1 - startPos));

    ELSEIF startInc = -1 AND startPos >= 1 THEN

      SET result = CONCAT(LEFT(subject, startPos), result);

    END IF;

  ELSE

    SET result = subject;

  END IF;

  RETURN result;

END//

DELIMITER ;

Demo

Rextester Demo

Limitations

1. This method is of course going to take a while when the subject
   string is large. Update: Have now added minimum and maximum match length parameters for improved efficiency when these are known (zero = unknown/unlimited).


2. It won't allow substitution of backreferences (e.g. 1, 2
   etc.) to replace capturing groups. If this functionality is needed, please see this answer which attempts to provide a workaround by updating the function to allow a secondary find and replace within each found match (at the expense of increased complexity).


3. If ^and/or $ is used in the pattern, they must be at the very start and very end respectively - e.g. patterns such as (^start|end$) are not supported.


4. There is a "greedy" flag to specify whether the overall matching should be greedy or non-greedy. Combining greedy and lazy matching within a single regular expression (e.g. a.*?b.*) is not supported.

Usage Examples

The function has been used to answer the following StackOverflow questions:

• How to count words in MySQL / regular expression
  replacer?


• How to extract the nth word and count word occurrences in a MySQL
  string?


• How to extract two consecutive digits from a text field in
  MySQL?


• How to remove all non-alpha numeric characters from a string in
  MySQL?


• How to replace every other instance of a particular character in a MySQL
  string?

You 'can' do it ... but it's not very wise ... this is about as daring as I'll try ... as far as full RegEx support your much better off using perl or the like.

UPDATE db.tbl

SET column = 

CASE 

WHEN column REGEXP '[[:<:]]WORD_TO_REPLACE[[:>:]]' 

THEN REPLACE(column,'WORD_TO_REPLACE','REPLACEMENT')

END 

WHERE column REGEXP '[[:<:]]WORD_TO_REPLACE[[:>:]]'

We can use IF condition in SELECT query as below:

Suppose that for anything with "ABC","ABC1","ABC2","ABC3",..., we want to replace with "ABC" then using REGEXP and IF() condition in the SELECT query, we can achieve this.

Syntax:

SELECT IF(column_name REGEXP 'ABC[0-9]$','ABC',column_name)

FROM table1 

WHERE column_name LIKE 'ABC%';

Example:

SELECT IF('ABC1' REGEXP 'ABC[0-9]$','ABC','ABC1');