Dynamic SQL with Dynamic Parameters - sql-server

Question

I am trying to write dynamic SQL that can accept up to 50 parameters. It can be 1 or 10 or 15. The limit is 50 from the main sproc but the input to the dynamic sql is not defined.
I have created this dynamic statement through a while loop. It will read the number of parameter in a table(3 in this example) and generates the statement below. I am not concerned with the performance of the while loop because the tables/input are very small:
--generated from while loop
DECLARE #rParam1 NVARCHAR(MAX)
DECLARE #rParam2 NVARCHAR(MAX)
DECLARE #rParam3 NVARCHAR(MAX)
SELECT #rParam1= Parameter_Name FROM [Template_Params] WHERE Key=12345 AND Sort_Order=1
SELECT #rParam2= Parameter_Name FROM [Template_Params] WHERE Key=12345 AND Sort_Order=2
SELECT #rParam3= Parameter_Name FROM [Template_Params] WHERE Key=12345 AND Sort_Order=3
DECLARE #BODY NVARCHAR(MAX);
SELECT #BODY = Body FROM [Template] WHERE Key=12345
SET #Body = REPLACE(#Body,#rparam1,#PARAM_Input1)
SET #Body = REPLACE(#Body,#rparam2,#PARAM_Input2)
SET #Body = REPLACE(#Body,#rparam3,#PARAM_Input3)
SELECT #BODY
This so far works good.
The stored procedure can have 50 inputs but for example I will limit to 5 (only used 3)
--this is from the main sproc
DECLARE #PARAM_Input1 NVARCHAR(MAX)='test',
#PARAM_Input2 NVARCHAR(MAX)='test1',
#PARAM_Input3 NVARCHAR(MAX)='test2',
#PARAM_Input4 NVARCHAR(MAX),
#PARAM_Input5 NVARCHAR(MAX),
#param_input6 nvarchar(max)
Now I need to get these values into the dynamic SQL so my final Dynamic statement should have
SET #Body = REPLACE(#Body,#rparam1,'test')
SET #Body = REPLACE(#Body,#rparam2,'test1')
SET #Body = REPLACE(#Body,#rparam3,'test2')
This is where I am stuck, I do not want to write the REPLACE Statement 50 times like this.
SET #SQL=REPLACE(#SQL,'#PARAM_Input1',''''+#PARAM_Input1+'''')
I tried a cursor but the name of the variable has to be dynamic and it's not in the same scope so the values from the sproc are not being passed.

Answer 1

It might not be possible in SQL to do what you have in mind. A solution could be if you can send a table as parameter to contain the information as below (or generate it dinamically:
ParameterName | Value
<value of #rParam1> | <value of #Param_Input1>
<value of #rParam2> | <value of #PARAM_Input2>
Then, update #BODY variable
SELECT #BODY = Body FROM [Template] WHERE Key=12345
UPDATE <TableParameter_Or_Variable>
SET #Body = REPLACE(#Body, ParameterName, Value)
I don't know how you obtain the values for #PARAM_InputX, but for `#rParamX' you can do something like:
INSERT INTO #Table
SELECT Parameter_Name AS ParameterName, null AS Value
[Template_Params] WHERE Key=12345
ORDER BY sort_order
and then update the rows accordingly. On #Table you can open a cursor and match the current row to #PARAM_InputX.