Using a multi-valued parameter in SSRS with dynamic SQL

Question

I am trying to use a multi-valued parameter in SSRS within a dynamic SQL query. In a static query I would use

SELECT myField
FROM myTable 
WHERE myField IN (@myParameter)

Using answers to this question (TSQL Passing MultiValued Reporting Services Parameter into Dynamic SQL) I have tried

-- SSRS requires the output field names to be static
CREATE TABLE #temp
(
    myField VARCHAR(100)
)

DECLARE @myQuery VARCHAR(5000) = 'SELECT myField
INTO #temp
FROM myTable
WHERE CHARINDEX('','' + myField + '','', '',''+''' + @myParameter + '''+'','') > 0'

EXEC (@myQuery)

This approach should work if the query understood @myParameter to be a string in a CSV format, but it doesn't seem to (as suggested by the link above). For example

SELECT @myParameter

won't work if there is more than one value selected.

I've also tried moving the parameter into a temporary table:

SELECT myField 
INTO #tempParameter
FROM @myParameter

-- SSRS requires the output field names to be static
CREATE TABLE #temp
(
    myField VARCHAR(100)
)

DECLARE @myQuery VARCHAR(5000) = 'SELECT myField
INTO #temp
FROM myTable
WHERE myField IN (SELECT myField FROM #tempParameter)'

EXEC (@myQuery)

I have SSRS 2012 and SQL Server 2012. NB: I need to use dynamic SQL for other reasons.

Answer 1

You don't need dynamic SQL for this. SSRS will (much to my dislike) inject multi value parameters when using a hard coded SQL statement in the report. Therefore you can just do something like the following:

SELECT *
FROM MyTable
WHERE MyColumn IN (@MyParameter)
  AND OtherCol > 0;

Before running the query, SSRS will remove @MyParameter and inject a delimited list of parameters.

The best guess, if you need to use dynamic SQL, is to use a string splitter and an SP (I use DelimitedSplit8K_LEAD here). SSRS will then pass the value of the parameter (@MultiParam) as a delimited string, and you can then split that in the dynamic statement:

CREATE PROC dbo.YourProc @MultiParam varchar(8000), @TableName sysname AS
BEGIN

    DECLARE @SQL nvarchar(MAX);
    SET @SQL = N'SELECT * FROM dbo.' + QUOTENAME(@TableName) + N' MT CROSS APPLY dbo.DelimitedSplit8K_LEAD (@MultiParam,'','') DS WHERE MT.MyColumn = DS.item;';

    EXEC sp_executesql @SQL, N'@MultiParam varchar(8000)', @MultiParam;
END;
GO

Answer 2

As I mentioned in the comments, your parameter is coming from SSRS as a single comma separated string as such:

@myParameter = 'FirstValue, Second Value Selected, Third Val'

When you try to use the parameter in the IN clause, it is read as such:

select *
from my table
where my column in ('FirstValue, Second Value Selected, Third Val')

This is invalid. The correct syntax would be like below, with quotes around each value.

select *
from my table
where my column in ('FirstValue', 'Second Value Selected', 'Third Val') 

So, you need to find a way to quote each value, which is hard because you don't know how many values there will be. So, the best thing to do is split that parameter into a table, and JOIN to it. Since we use a table-valued function in this example, we use CROSS APPLY.

First, create the function that Jeff Moden made, and so many people use. Or, use STRING_SPLIT if you are on 2016 onward, or make your own. However, anything that uses a recursive CTE, WHILE loop, cursor, etc will be far slower than the one below.

CREATE FUNCTION [dbo].[DelimitedSplit8K]
--===== Define I/O parameters
        (@pString VARCHAR(8000), @pDelimiter CHAR(1))
--WARNING!!! DO NOT USE MAX DATA-TYPES HERE!  IT WILL KILL PERFORMANCE!
RETURNS TABLE WITH SCHEMABINDING AS
 RETURN
--===== "Inline" CTE Driven "Tally Table" produces values from 1 up to 10,000...
     -- enough to cover VARCHAR(8000)
  WITH E1(N) AS (
                 SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
                 SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
                 SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
                ),                          --10E+1 or 10 rows
       E2(N) AS (SELECT 1 FROM E1 a, E1 b), --10E+2 or 100 rows
       E4(N) AS (SELECT 1 FROM E2 a, E2 b), --10E+4 or 10,000 rows max
 cteTally(N) AS (--==== This provides the "base" CTE and limits the number of rows right up front
                     -- for both a performance gain and prevention of accidental "overruns"
                 SELECT TOP (ISNULL(DATALENGTH(@pString),0)) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
                ),
cteStart(N1) AS (--==== This returns N+1 (starting position of each "element" just once for each delimiter)
                 SELECT 1 UNION ALL
                 SELECT t.N+1 FROM cteTally t WHERE SUBSTRING(@pString,t.N,1) = @pDelimiter
                ),
cteLen(N1,L1) AS(--==== Return start and length (for use in substring)
                 SELECT s.N1,
                        ISNULL(NULLIF(CHARINDEX(@pDelimiter,@pString,s.N1),0)-s.N1,8000)
                   FROM cteStart s
                )
--===== Do the actual split. The ISNULL/NULLIF combo handles the length for the final element when no delimiter is found.
 SELECT ItemNumber = ROW_NUMBER() OVER(ORDER BY l.N1),
        Item       = SUBSTRING(@pString, l.N1, l.L1)
   FROM cteLen l
;

Then, you simply call that with your function like so:

DB FIDDLE DEMO

create table mytable (Names varchar(64))

insert into mytable values ('Bob'),('Mary'),('Tom'),('Frank')

--this is your parameter from SSRS    
declare @var varchar(4000) = 'Bob,Mary,Janice,Scarlett'

select distinct mytable.*
from mytable
cross apply dbo.DelimitedSplit8K(@var,',') spt
where spt.Item = mytable.Names

Answer 3

The split string solution didn't work for me either, and I tried to figure out what type the Multi parameter variable in SSRS actually is so I somehow could work with it. The multi parameter variable was @productIds and the type of the data field was UNIQUEIDENTIFIER. So I wrote the type to a log table

INSERT INTO DebugLog 
SELECT CAST(SQL_VARIANT_PROPERTY(@productIds,'BaseType') AS VARCHAR(MAX))

When I selected one value the type was NVARCHAR, however when I selected two or more values I got an error

System.Data.SqlClient.SqlException: The sql_variant_property function requires 2 argument(s).

So I stopped trying to figure out what a multi parameter variable actually was, I already spent to much time.

Since I had the values in a table I could select the values from that table into a temp table and then join on that in the dynamic built query

SELECT p.Id
INTO #tempProdIds
FROM Products p WHERE p.Id IN @productIds

SET @query +='
....
JOIN #tempProdIds tpi on tl.Product = tpi.Id
....
'
EXEC(@query)