transfer multirow parameters to one var

1. Create test table

CREATE TABLE dbo.Params(
   id int IDENTITY(1,1) NOT NULL
 , param varchar(50) NULL )

2. Add test records for parameters

INSERT INTO dbo.Params (param)
VALUES ('some = 1')
  , ('some = 2')
  , ('some = 3')
  , ('some = 4')
  , ('some = 5')

3. Get parameters as one row using PIVOT

SELECT 
   isnull([1],'') [param1]
 , isnull([2],'') [param2]
 , isnull([3],'') [param3]
 , isnull([4],'') [param4]
 , isnull([5],'') [param5]
FROM (
 SELECT row_number() OVER (ORDER BY param) AS rn, param 
 FROM dbo.Params 
 WHERE param IS NOT NULL
) S
PIVOT
(
 MAX(param)
 FOR rn IN ([1],[2],[3], [4], [5])
) AS PivotTable;

4. Result of SELECT

param1    param2    param3    param4    param5
--------- --------- --------- --------- ----------
some = 1  some = 2  some = 3  some = 4  some = 5
(1 row(s) affected)

5. Use variable expression to get one string

(@[User::param1] == "")?"":@[User::param1] 
+ ( (@[User::param2] == "")?"": " AND " + @[User::param2] )
+ ( (@[User::param3] == "")?"": " AND " + @[User::param3] )
+ ( (@[User::param4] == "")?"": " AND " + @[User::param4] )
+ ( (@[User::param5] == "")?"": " AND " + @[User::param5] )

6. Now we have parameters combined in one variable

some = 1  AND some = 2  AND some = 3  AND some = 4  AND some = 5