how to replace multiple strings together in Oracle

Solution 1:

Although it is not one call, you can nest the replace() calls:

SET mycol = replace( replace(mycol, '{1}', 'myoneval'), '{2}', mytwoval)

Solution 2:

If there are many variables to replace and you have them in another table and if the number of variables is variable you can use a recursive CTE to replace them. An example below. In table fg_rulez you put the strings with their replacement. In table fg_data you have your input strings.

set define off;
drop table fg_rulez
create table fg_rulez as 
  select 1 id,'<' symbol, 'less than' text from dual
  union all select 2, '>', 'great than' from dual
  union all select 3, '$', 'dollars' from dual
  union all select 4, '&', 'and' from dual;
drop table fg_data;
create table fg_Data AS(
   SELECT 'amount $ must be < 1 & > 2' str FROM dual
   union all
   SELECT 'John is >  Peter & has many $' str FROM dual
   union all
   SELECT 'Eliana is < mary & do not has many $' str FROM dual

   );


WITH  q(str, id) as (
  SELECT str, 0 id 
  FROM fg_Data 
     UNION ALL
  SELECT replace(q.str,symbol,text), fg_rulez.id
  FROM q 
  JOIN fg_rulez 
    ON q.id = fg_rulez.id - 1
)
SELECT str from q where id = (select max(id) from fg_rulez);

So, a single replace.

Result:

amount dollars must be less than 1 and great than 2 
John is great than Peter and has many dollars 
Eliana is less than mary and do not  has many dollars

The terminology symbol instead of variable comes from this duplicated question.

Oracle 11gR2

Solution 3:

If the number of values to replace is too big or you need to be able to easily maintain it, you could also split the string, use a dictionary table and finally aggregate the results

In the example below I'm assuming that the words in your string are separated with blankspaces and the wordcount in the string will not be bigger than 100 (pivot table cardinality)

with Dict as
 (select '{1}' String, 'myfirstval' Repl from dual
   union all
  select '{2}' String, 'mysecondval' Repl from dual
   union all
  select '{3}' String, 'mythirdval' Repl from dual
   union all  
  select '{Nth}' String, 'myNthval' Repl from dual  

 )
,MyStrings as
 (select 'This  is the first example {1} ' Str, 1 strnum from dual
  union all
  select 'In the Second example all values are shown {1} {2} {3} {Nth} ', 2  from dual
  union all
  select '{3} Is the value for the third', 3 from dual
  union all
  select '{Nth} Is the value for the Nth', 4 from dual  
  )
,pivot as (
  Select Rownum Pnum
  From dual
  Connect By Rownum <= 100   
  )
,StrtoRow as
(
SELECT rownum rn
      ,ms.strnum
      ,REGEXP_SUBSTR (Str,'[^ ]+',1,pv.pnum) TXT
  FROM MyStrings ms
      ,pivot pv
where REGEXP_SUBSTR (Str,'[^ ]+',1,pv.pnum) is not null
)
Select Listagg(NVL(Repl,TXT),' ') within group (order by rn) 
from
(
Select sr.TXT, d.Repl, sr.strnum, sr.rn
  from StrtoRow sr
      ,dict d
 where sr.TXT = d.String(+) 
order by strnum, rn 
) group by strnum

Solution 4:

Let's write the same sample as a CTE only:

with fg_rulez as (
  select 1 id,'<' symbol, 'less than' text from dual
  union all select 2, '>', 'greater than' from dual
   union all select 3, '$', 'dollars' from dual
  union all select 4, '+', 'and' from dual
),  fg_Data AS (
   SELECT 'amount $ must be < 1 + > 2' str FROM dual
   union all
   SELECT 'John is > Peter + has many $' str FROM dual
   union all
   SELECT 'Eliana is < mary + do not has many $' str FROM dual
), q(str, id) as (
  SELECT str, 0 id 
  FROM fg_Data 
     UNION ALL
  SELECT replace(q.str,symbol,text), fg_rulez.id
  FROM q 
  JOIN fg_rulez 
    ON q.id = fg_rulez.id - 1
)
SELECT str from q where id = (select max(id) from fg_rulez);