Replace placeholder content in result set - sql-server

Question

I have this table as a simple example, with food items:
Table: FoodItem
1 Burgers
2 French Fries
3 Pizzas
and I have another table with phrases like these:
Table: Phrase
1 I want {1} and {2}!
2 I just want {3}.
I want to create an sp that grabs all the phrases from the phrase table and replaces the placeholder parts with content from the food table, like this:
I want Burgers and French Fries!
I just want Pizzas.
How can I accomplish this? I already tried "like" and "patindex", but I'm unsure of whether these are even suited for this task.

Answer 1

For a little number of replacements and small amount of data you can use recursive CTE (I have seen bad performance when a lot of replacements are performed). Something like this:
Declare #Phrase table (ID int,Phrase varchar(100))
Insert into #Phrase values
(1,'I want {1} and {2}!')
,(2,'I just want {3}.')
,(3,'i just don not like {1} and {3}');
Declare #FoodItem table (ID int, MapTo varchar(100))
Insert Into #FoodItem values
(1 ,'Burgers')
,(2 ,'French Fries')
,(3 ,'Pizza');
With DataSource AS
(
SELECT ID
,Phrase
,1 as level
FROM #Phrase
UNION ALL
SELECT DS.[ID]
,cast(REPLACE(ds.Phrase, '{'+ CAST(DS.[Level] AS VARCHAR(8)) +'}', FI.[MapTo]) as varchar(100))
,level + 1 as level
FROM DataSource DS
INNER JOIN #FoodItem FI
ON DS.[level] = FI.[ID]
)
SELECT *
FROM DataSource
WHERE level = (SELECT max(id) from #FoodItem) + 1;
I am sure this can be improved further.
If you are going to work with huge amount of data it will be good to implement SQL CLR function for replacing multiple strings and concatenating strings.
So, for each row you will have something like this:
(1,'I want {1} and {2}!', '{1}|{2}','Burgers|French Fries')
,(2,'I just want {3}.', '{3}', 'Pizza')
,(3,'i just don not like {1} and {3}', '{1}|{3}','Burgers|Pizza');
Then your function with accept the three columns and perform the replace internally.

Answer 2

Example
Declare #Phrase table (ID int,Phrase varchar(100))
Insert into #Phrase values
(1,'I want {1} and {2}!')
,(2,'I just want {3}.')
Declare #FoodItem table (ID int, MapTo varchar(100))
Insert Into #FoodItem values
(1 ,'Burgers')
,(2 ,'French Fries')
,(3 ,'Pizza')
Select A.ID
,NewStr = replace(replace(B.S,' ||',''),'|| ','')
From #Phrase A
Cross Apply (
Select S = Stuff((Select ' ' +coalesce(MapTo,RetVal)
From (
Select RetSeq = Row_Number() over (Order By (Select null))
,RetVal = LTrim(RTrim(B.i.value('(./text())[1]', 'varchar(max)')))
From (Select x = Cast('<x>' + replace((Select replace(replace(replace(A.Phrase,'{','|| {'),'}','} ||'),' ','§§Split§§') as [*] For XML Path('')),'§§Split§§','</x><x>')+'</x>' as xml).query('.')) as A
Cross Apply x.nodes('x') AS B(i)
) B1
Left Join #FoodItem B2 on B1.RetVal = concat('{',B2.ID,'}')
Order by RetSeq
For XML Path ('')),1,1,'')
) B
Returns
ID NewStr
1 I want Burgers and French Fries!
2 I just want Pizza.
Edit - It may be more performat to create a UDF which does something like the
following
Declare #S varchar(max) = 'I want {1} and {2}!'
Select #S = replace(#S,concat('{',ID,'}'),MapTo)
From FoodItem
Select #S
Returns
I want Burgers and French Fries!