Replace some variables by data of another table in sql oracle - sql

Question

I have a table with two columns
type
TXT
A
this is some text for %1 and %2
B
this is another step for %1
in a translation table I have the signification of the variables %X that looks like
Type
variable
descr
A
%1
#person1#
A
%2
#person2#
B
%1
#manager#
I want to replace in my first table all the variables by the description, so the result has to looks like this:
type
TXT
A
this is some text for #person1# and #person2#
B
this is another step for #manager#
I tried with a replace, but I didn't figured out how to make it work

Answer 1

To replace all variables you could use a recursive algorithm:
with data(typ, txt) as (
select 'A', 'this is some text for %1 and %2' from dual union all
select 'B', 'this is another step for %1' from dual
),
translations(typ, var, description) as (
select 'A', '%1', '#person1#' from dual union all
select 'A', '%2', '#person2#' from dual union all
select 'B', '%1', '#manager#' from dual -- union all
),
rtranslations(typ, var, description,rn) as (
select t.*, row_number() over(partition by typ order by var) as rn
from translations t
),
replacecte(typ, txt, replaced_txt, rn) as (
select d.typ, d.txt, replace(d.txt, t.var, t.description), t.rn
from data d
join rtranslations t on t.typ = d.typ
where t.rn = 1
union all
select r.typ, r.txt, replace(r.replaced_txt, t.var, t.description), t.rn
from replacecte r
join rtranslations t on t.typ = r.typ and t.rn = r.rn + 1
)
select r.typ, r.txt, replaced_txt from replacecte r
where rn = length(txt) - length(replace(txt,'%',''))
;

Answer 2

You can also do it this way without recursion. data and descr are of course just mock ups for your tables, you would not need any WITH clauses. This method uses the steps (1) break up the sentences into words, (2) outer join using those words to your description table, replacing any matches with the description values, (3) reassemble the words back into sentences using LISTAGG.
WITH data AS(SELECT 'A' type, 'this is some text for %1 and %2' txt FROM dual
UNION ALL
SELECT 'B' type, 'this is another step for %1' txt FROM dual
),
descr AS (SELECT 'A' type, '%1' variable,'#person1#' description FROM dual
UNION ALL
SELECT 'A' type, '%2' variable,'#person2#' description FROM dual
UNION ALL
SELECT 'B' type, '%1' variable,'#manager#' description FROM dual)
SELECT type,
LISTAGG(new_word,' ') WITHIN GROUP (ORDER BY seq) txt
FROM (SELECT x.type,
NVL(descr.description,x.word) new_word,
seq
FROM (SELECT type,SUBSTR(' '||txt,INSTR(' '||txt,' ',1,seq)+1,INSTR(' '||txt||' ',' ',1,seq+1) - (INSTR(' '||txt,' ',1,seq)+1)) word,seq
FROM data,
(SELECT ROWNUM seq FROM dual CONNECT BY LEVEL <= 50) x) x,
descr
WHERE x.type = descr.type(+)
AND x.word = descr.variable(+))
GROUP BY type

Answer 3

You could use PIVOT to get the var values from rows into columns (geting all vars in the same row with text) and then do multiple replaces depending on number of var values:
SELECT t.A_TYPE,
CASE WHEN d.V3 Is Not Null THEN REPLACE(REPLACE(REPLACE(t.TXT, '%1', d.V1), '%2', d.V2), '%3', d.V3)
WHEN d.V2 Is Not Null THEN REPLACE(REPLACE(t.TXT, '%1', d.V1), '%2', d.V2)
WHEN d.V1 Is Not Null THEN REPLACE(t.TXT, '%1', d.V1)
ELSE t.TXT
END "TXT"
FROM tbl t
INNER JOIN ( SELECT *
FROM ( Select A_TYPE, VAR, DESCRIPTION FROM descr )
PIVOT ( MAX(DESCRIPTION) For VAR IN('%1' "V1", '%2' "V2", '%' "V3") )
) d ON(d.A_TYPE = t.A_TYPE)
With sample data as:
WITH
tbl (A_TYPE, TXT) AS
(
Select 'A', 'this is some text for %1 and %2' From Dual Union All
Select 'B', 'this is another step for %1' From dual
),
descr (A_TYPE, VAR, DESCRIPTION) AS
(
Select 'A', '%1', '#person1#' From Dual UNION ALL
Select 'A', '%2', '#person2#' From Dual UNION ALL
Select 'B', '%1', '#manager#' From Dual
)
... the result should be
A_TYPE TXT
------ -----------------------------------------------
A this is some text for #person1# and #person2#
B this is another step for #manager#