Replace multiple tags in a row in select statement from another table

I have two tables.
One is answer_step_dtl
Another is tag_mst as follow

Ans_code                      Ans_Desc
-------------------------------------------
50000000000000005770       Enter <B><APN></B> and press Ok.       
40000000000000000164       Enter <B><ACCOUNTNAME></B> in connection name.
40000000000000000165       Enter <B><ACCOUNTNAME></B> in <APN>.

and so on.

And my tag_mst has values like this

TAG_CODE                    TAG_NAME          TAG_VALUE
-------------------------------------------------------
100                          <APN>            EXAMPLE.COM
101                          <ACCOUNTNAME>    EXAMPLE

Now my requirement is this I want to select answer form answer table with replaced value of tag mast. There can be more than one tag in the one ans_desc .

I was thinking the approach

  • Loop through the result of answer_dtl fetch the tags from individual record

  • loop through the multiple tags in the record and then replace the tag

  • store in a temporary table and then open the cursor for new tem table.
  • Is this is the approach. Or is there any easy approach of doing this.


    Edit: Bonus query using (recursive) CTE, inspired by a note from @Rob van Wijk, needs 11g(R2?):

    SQL> WITH data AS (
      2     SELECT ans_code, Ans_Desc, tag_name, tag_value,
      3            row_number() OVER (partition BY ans_code ORDER BY t.rowid) no,
      4            row_number() OVER
      5               (partition BY ans_code ORDER BY t.rowid DESC) is_last
      6        FROM answer_step_dtl a
      7        JOIN tag_mst t ON a.ans_desc LIKE '%' || t.tag_name || '%'
      8  ), n(ans_code, no, is_last, replaced) AS (
      9     SELECT ans_code, no n, is_last,
     10            replace (ans_desc, tag_name, tag_value) replaced
     11       FROM data
     12      WHERE no = 1
     13     UNION ALL
     14     SELECT d.ans_code, d.no, d.is_last,
     15            replace (n.replaced, d.tag_name, d.tag_value) replaced
     16       FROM data d
     17       JOIN n ON d.ans_code = n.ans_code
     18        AND d.no = n.no + 1
     19  )
     20  SELECT *
     21    FROM n
     22   WHERE is_last=1;
    
    ANS_CODE             NO IS_LAST REPLACED
    -------------------- -- ------- ---------------------------------------
    40000000000000000164  1       1 Enter <B>EXAMPLE</B> in connection
    50000000000000005770  1       1 Enter <B>EXAMPLE.COM</B> and press Ok.
    40000000000000000165  2       1 Enter <B>EXAMPLE</B> in EXAMPLE.COM.
    

    Initial answer:

    You can use of a PL/SQL function. The following will work even if there are several tags to be replaced:

    CREATE OR REPLACE FUNCTION replacetags(p_desc VARCHAR2)
       RETURN VARCHAR2 IS
       l_result  LONG := p_desc;
       l_tag_pos INTEGER := 1;
       l_tag     tag_mst.tag_name%TYPE;
    BEGIN
       LOOP
          l_tag     := regexp_substr(l_result, '<[^<]+>', l_tag_pos);
          l_tag_pos := regexp_instr(l_result, '<[^<]+>', l_tag_pos) + 1;
          EXIT WHEN l_tag IS NULL;
          BEGIN
             SELECT replace(l_result, l_tag, tag_value)
               INTO l_result
               FROM tag_mst
              WHERE tag_name = l_tag;
          EXCEPTION
             WHEN no_data_found THEN
                NULL; -- tag doesn't exist in tag_mst
          END;
       END LOOP;
       RETURN l_result;
    END;
    
    SQL> SELECT ans_code, replacetags(ans_desc)
      2    FROM answer_step_dtl;
    
    ANS_CODE              REPLACETAGS(ANS_DESC)
    --------------------- ----------------------------------------
    50000000000000005770  Enter <B>EXAMPLE.COM</B> and press Ok.
    40000000000000000164  Enter <B>EXAMPLE</B> in connection
    40000000000000000165  Enter <B>EXAMPLE</B> in EXAMPLE.COM.
    

    try this:

    select d."Ans_code",replace("Ans_Desc","TAG_NAME","TAG_VALUE")
    from   answer_step_dtl d, tag_mst m
    where "Ans_Desc" like '%'|| "TAG_NAME" || '%'
    


    SQL fiddle demo

    链接地址: http://www.djcxy.com/p/66052.html

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