[oracle] Multiple REPLACE function in Oracle

I am using the REPLACE function in oracle to replace values in my string like;

 SELECT REPLACE('THE NEW VALUE IS #VAL1#','#VAL1#','55') from dual

So this is OK to replace one value, but what about 20+, should I use 20+ REPLACE function or is there a more practical solution.

All ideas are welcome.

Bear in mind the consequences

SELECT REPLACE(REPLACE('TEST123','123','456'),'45','89') FROM DUAL;

will replace the 123 with 456, then find that it can replace the 45 with 89. For a function that had an equivalent result, it would have to duplicate the precedence (ie replacing the strings in the same order).

Similarly, taking a string 'ABCDEF', and instructing it to replace 'ABC' with '123' and 'CDE' with 'xyz' would still have to account for a precedence to determine whether it went to '123EF' or ABxyzF'.

In short, it would be difficult to come up with anything generic that would be simpler than a nested REPLACE (though something that was more of a sprintf style function would be a useful addition).

The accepted answer to how to replace multiple strings together in Oracle suggests using nested REPLACE statements, and I don't think there is a better way.

If you are going to make heavy use of this, you could consider writing your own function:

CREATE TYPE t_text IS TABLE OF VARCHAR2(256);

CREATE FUNCTION multiple_replace(
  in_text IN VARCHAR2, in_old IN t_text, in_new IN t_text
)
  RETURN VARCHAR2
AS
  v_result VARCHAR2(32767);
BEGIN
  IF( in_old.COUNT <> in_new.COUNT ) THEN
    RETURN in_text;
  END IF;
  v_result := in_text;
  FOR i IN 1 .. in_old.COUNT LOOP
    v_result := REPLACE( v_result, in_old(i), in_new(i) );
  END LOOP;
  RETURN v_result;
END;

and then use it like this:

SELECT multiple_replace( 'This is #VAL1# with some #VAL2# to #VAL3#',
                         NEW t_text( '#VAL1#', '#VAL2#', '#VAL3#' ),
                         NEW t_text( 'text', 'tokens', 'replace' )
                       )
FROM dual

This is text with some tokens to replace

If all of your tokens have the same format ('#VAL' || i || '#'), you could omit parameter in_old and use your loop-counter instead.

I have created a general multi replace string Oracle function by a table of varchar2 as parameter. The varchar will be replaced for the position rownum value of table.

For example:

Text: Hello {0}, this is a {2} for {1}
Parameters: TABLE('world','all','message')

Returns:

Hello world, this is a message for all.

You must create a type:

CREATE OR REPLACE TYPE "TBL_VARCHAR2" IS TABLE OF VARCHAR2(250);

The funcion is:

CREATE OR REPLACE FUNCTION FN_REPLACETEXT(
    pText IN VARCHAR2, 
    pPar IN TBL_VARCHAR2
) RETURN VARCHAR2
IS
    vText VARCHAR2(32767);
    vPos INT;
    vValue VARCHAR2(250);

    CURSOR cuParameter(POS INT) IS
    SELECT VAL
        FROM
            (
            SELECT VAL, ROWNUM AS RN 
            FROM (
                  SELECT COLUMN_VALUE VAL
                  FROM TABLE(pPar)
                  )
            )
        WHERE RN=POS+1;
BEGIN
    vText := pText;
    FOR i IN 1..REGEXP_COUNT(pText, '[{][0-9]+[}]') LOOP
        vPos := TO_NUMBER(SUBSTR(REGEXP_SUBSTR(pText, '[{][0-9]+[}]',1,i),2, LENGTH(REGEXP_SUBSTR(pText, '[{][0-9]+[}]',1,i)) - 2));

        OPEN cuParameter(vPos);
        FETCH cuParameter INTO vValue;
        IF cuParameter%FOUND THEN
            vText := REPLACE(vText, REGEXP_SUBSTR(pText, '[{][0-9]+[}]',1,i), vValue);
        END IF;
        CLOSE cuParameter;
    END LOOP;

    RETURN vText;

EXCEPTION
      WHEN OTHERS
      THEN
         RETURN pText;
END FN_REPLACETEXT;
/

Usage:

TEXT_RETURNED := FN_REPLACETEXT('Hello {0}, this is a {2} for {1}', TBL_VARCHAR2('world','all','message'));

In case all your source and replacement strings are just one character long, you can simply use the TRANSLATE function:

  SELECT translate('THIS IS UPPERCASE', 'THISUP', 'thisup') 
  FROM DUAL

See the Oracle documentation for details.

This is an old post, but I ended up using Peter Lang's thoughts, and did a similar, but yet different approach. Here is what I did:

CREATE OR REPLACE FUNCTION multi_replace(
                        pString IN VARCHAR2
                        ,pReplacePattern IN VARCHAR2
) RETURN VARCHAR2 IS
    iCount  INTEGER;
    vResult VARCHAR2(1000);
    vRule   VARCHAR2(100);
    vOldStr VARCHAR2(50);
    vNewStr VARCHAR2(50);
BEGIN
    iCount := 0;
    vResult := pString;
    LOOP
        iCount := iCount + 1;

        -- Step # 1: Pick out the replacement rules
        vRule := REGEXP_SUBSTR(pReplacePattern, '[^/]+', 1, iCount);

        -- Step # 2: Pick out the old and new string from the rule
        vOldStr := REGEXP_SUBSTR(vRule, '[^=]+', 1, 1);
        vNewStr := REGEXP_SUBSTR(vRule, '[^=]+', 1, 2);

        -- Step # 3: Do the replacement
        vResult := REPLACE(vResult, vOldStr, vNewStr);

        EXIT WHEN vRule IS NULL;
    END LOOP;

    RETURN vResult;
END multi_replace;

Then I can use it like this:

SELECT  multi_replace(
                        'This is a test string with a #, a $ character, and finally a & character'
                        ,'#=%23/$=%24/&=%25'
        )
FROM dual

This makes it so that I can can any character/string with any character/string.

I wrote a post about this on my blog.