Using a multi-valued parameter in SSRS with dynamic SQL - sql-server

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)