How to use table variable in a dynamic sql statement? - sql

Question

In my stored procedure I declared two table variables on top of my procedure. Now I am trying to use that table variable within a dynamic sql statement but I get this error at the time of execution of that procedure. I am using Sql Server 2008.
This is how my query looks like,
set #col_name = 'Assoc_Item_'
+ Convert(nvarchar(2), #curr_row1);
set #sqlstat = 'update #RelPro set '
+ #col_name
+ ' = (Select relsku From #TSku Where tid = '
+ Convert(nvarchar(2), #curr_row1) + ') Where RowID = '
+ Convert(nvarchar(2), #curr_row);
Exec(#sqlstat);
And I get the following errors,
Must declare the table variable "#RelPro".
Must declare the table variable "#TSku".
I have tried to take the table outside of the string block of dynamic query but to no avail.

Answer 1

On SQL Server 2008+ it is possible to use Table Valued Parameters to pass in a table variable to a dynamic SQL statement as long as you don't need to update the values in the table itself.
So from the code you posted you could use this approach for #TSku but not for #RelPro
Example syntax below.
CREATE TYPE MyTable AS TABLE
(
Foo int,
Bar int
);
GO
DECLARE #T AS MyTable;
INSERT INTO #T VALUES (1,2), (2,3)
SELECT *,
sys.fn_PhysLocFormatter(%%physloc%%) AS [physloc]
FROM #T
EXEC sp_executesql
N'SELECT *,
sys.fn_PhysLocFormatter(%%physloc%%) AS [physloc]
FROM #T',
N'#T MyTable READONLY',
#T=#T
The physloc column is included just to demonstrate that the table variable referenced in the child scope is definitely the same one as the outer scope rather than a copy.

Answer 2

Your EXEC executes in a different context, therefore it is not aware of any variables that have been declared in your original context. You should be able to use a temp table instead of a table variable as shown in the simple demo below.
create table #t (id int)
declare #value nchar(1)
set #value = N'1'
declare #sql nvarchar(max)
set #sql = N'insert into #t (id) values (' + #value + N')'
exec (#sql)
select * from #t
drop table #t

Answer 3

You don't have to use dynamic SQL
update
R
set
Assoc_Item_1 = CASE WHEN #curr_row = 1 THEN foo.relsku ELSE Assoc_Item_1 END,
Assoc_Item_2 = CASE WHEN #curr_row = 2 THEN foo.relsku ELSE Assoc_Item_2 END,
Assoc_Item_3 = CASE WHEN #curr_row = 3 THEN foo.relsku ELSE Assoc_Item_3 END,
Assoc_Item_4 = CASE WHEN #curr_row = 4 THEN foo.relsku ELSE Assoc_Item_4 END,
Assoc_Item_5 = CASE WHEN #curr_row = 5 THEN foo.relsku ELSE Assoc_Item_5 END,
...
from
(Select relsku From #TSku Where tid = #curr_row1) foo
CROSS JOIN
#RelPro R
Where
R.RowID = #curr_row;

Answer 4

You can't do this because the table variables are out of scope.
You would have to declare the table variable inside the dynamic SQL statement or create temporary tables.
I would suggest you read this excellent article on dynamic SQL.
http://www.sommarskog.se/dynamic_sql.html

Answer 5

Well, I figured out the way and thought to share with the people out there who might run into the same problem.
Let me start with the problem I had been facing,
I had been trying to execute a Dynamic Sql Statement that used two temporary tables I declared at the top of my stored procedure, but because that dynamic sql statment created a new scope, I couldn't use the temporary tables.
Solution:
I simply changed them to Global Temporary Variables and they worked.
Find my stored procedure underneath.
CREATE PROCEDURE RAFCustom_Room_GetRelatedProducts
-- Add the parameters for the stored procedure here
#PRODUCT_SKU nvarchar(15) = Null
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
IF OBJECT_ID('tempdb..##RelPro', 'U') IS NOT NULL
BEGIN
DROP TABLE ##RelPro
END
Create Table ##RelPro
(
RowID int identity(1,1),
ID int,
Item_Name nvarchar(max),
SKU nvarchar(max),
Vendor nvarchar(max),
Product_Img_180 nvarchar(max),
rpGroup int,
Assoc_Item_1 nvarchar(max),
Assoc_Item_2 nvarchar(max),
Assoc_Item_3 nvarchar(max),
Assoc_Item_4 nvarchar(max),
Assoc_Item_5 nvarchar(max),
Assoc_Item_6 nvarchar(max),
Assoc_Item_7 nvarchar(max),
Assoc_Item_8 nvarchar(max),
Assoc_Item_9 nvarchar(max),
Assoc_Item_10 nvarchar(max)
);
Begin
Insert ##RelPro(ID, Item_Name, SKU, Vendor, Product_Img_180, rpGroup)
Select distinct zp.ProductID, zp.Name, zp.SKU,
(Select m.Name From ZNodeManufacturer m(nolock) Where m.ManufacturerID = zp.ManufacturerID),
'http://s0001.server.com/is/sw11/DG/' +
(Select m.Custom1 From ZNodeManufacturer m(nolock) Where m.ManufacturerID = zp.ManufacturerID) +
'_' + zp.SKU + '_3?$SC_3243$', ep.RoomID
From Product zp(nolock) Inner Join RF_ExtendedProduct ep(nolock) On ep.ProductID = zp.ProductID
Where zp.ActiveInd = 1 And SUBSTRING(zp.SKU, 1, 2) <> 'GC' AND zp.Name <> 'PLATINUM' AND zp.SKU = (Case When #PRODUCT_SKU Is Not Null Then #PRODUCT_SKU Else zp.SKU End)
End
declare #curr_row int = 0,
#tot_rows int= 0,
#sku nvarchar(15) = null;
IF OBJECT_ID('tempdb..##TSku', 'U') IS NOT NULL
BEGIN
DROP TABLE ##TSku
END
Create Table ##TSku (tid int identity(1,1), relsku nvarchar(15));
Select #curr_row = (Select MIN(RowId) From ##RelPro);
Select #tot_rows = (Select MAX(RowId) From ##RelPro);
while #curr_row <= #tot_rows
Begin
select #sku = SKU from ##RelPro where RowID = #curr_row;
truncate table ##TSku;
Insert ##TSku(relsku)
Select distinct top(10) tzp.SKU From Product tzp(nolock) INNER JOIN
[INTRANET].raf_FocusAssociatedItem assoc(nolock) ON assoc.associatedItemID = tzp.SKU
Where (assoc.isActive=1) And (tzp.ActiveInd = 1) AND (assoc.productID = #sku)
declare #curr_row1 int = (Select Min(tid) From ##TSku),
#tot_rows1 int = (Select Max(tid) From ##TSku);
If(#tot_rows1 <> 0)
Begin
While #curr_row1 <= #tot_rows1
Begin
declare #col_name nvarchar(15) = null,
#sqlstat nvarchar(500) = null;
set #col_name = 'Assoc_Item_' + Convert(nvarchar(2), #curr_row1);
set #sqlstat = 'update ##RelPro set ' + #col_name + ' = (Select relsku From ##TSku Where tid = ' + Convert(nvarchar(2), #curr_row1) + ') Where RowID = ' + Convert(nvarchar(2), #curr_row);
Exec(#sqlstat);
set #curr_row1 = #curr_row1 + 1;
End
End
set #curr_row = #curr_row + 1;
End
Select * From ##RelPro;
END
GO

Answer 6

I don't think that is possible (though refer to the update below); as far as I know a table variable only exists within the scope that declared it. You can, however, use a temp table (use the create table syntax and prefix your table name with the # symbol), and that will be accessible within both the scope that creates it and the scope of your dynamic statement.
UPDATE: Refer to Martin Smith's answer for how to use a table-valued parameter to pass a table variable in to a dynamic SQL statement. Also note the limitation mentioned: table-valued parameters are read-only.

Answer 7

Here is an example of using a dynamic T-SQL query and then extracting the results should you have more than one column of returned values (notice the dynamic table name):
DECLARE
#strSQLMain nvarchar(1000),
#recAPD_number_key char(10),
#Census_sub_code varchar(1),
#recAPD_field_name char(100),
#recAPD_table_name char(100),
#NUMBER_KEY varchar(10),
if object_id('[Permits].[dbo].[myTempAPD_Txt]') is not null
DROP TABLE [Permits].[dbo].[myTempAPD_Txt]
CREATE TABLE [Permits].[dbo].[myTempAPD_Txt]
(
[MyCol1] char(10) NULL,
[MyCol2] char(1) NULL,
)
-- an example of what #strSQLMain is : #strSQLMain = SELECT #recAPD_number_key = [NUMBER_KEY], #Census_sub_code=TEXT_029 FROM APD_TXT0 WHERE Number_Key = '01-7212'
SET #strSQLMain = ('INSERT INTO myTempAPD_Txt SELECT [NUMBER_KEY], '+ rtrim(#recAPD_field_name) +' FROM '+ rtrim(#recAPD_table_name) + ' WHERE Number_Key = '''+ rtrim(#Number_Key) +'''')
EXEC (#strSQLMain)
SELECT #recAPD_number_key = MyCol1, #Census_sub_code = MyCol2 from [Permits].[dbo].[myTempAPD_Txt]
DROP TABLE [Permits].[dbo].[myTempAPD_Txt]

Answer 8

Using Temp table solves the problem but I ran into issues using Exec so I went with the following solution of using sp_executesql:
Create TABLE #tempJoin ( Old_ID int, New_ID int);
declare #table_name varchar(128);
declare #strSQL nvarchar(3072);
set #table_name = 'Object';
--build sql sting to execute
set #strSQL='INSERT INTO '+#table_name+' SELECT '+#columns+' FROM #tempJoin CJ
Inner Join '+#table_name+' sourceTbl On CJ.Old_ID = sourceTbl.Object_ID'
**exec sp_executesql #strSQL;**