How Can I Use Table Variables with Dynamic SQL in SQL Server 2008?

Dynamic SQL and Table Variables: SQL Server 2008 Workarounds

Stored procedures often require dynamically executed SQL statements that interact with table variables. However, SQL Server 2008 presents challenges when directly using table variables within dynamic SQL, frequently resulting in "Must declare the table variable" errors.

This limitation stems from SQL Server 2008's restrictions on modifying table variables inside dynamic SQL statements. Direct updates or modifications are not permitted.

The solution involves using Table-Valued Parameters (TVPs). TVPs function as read-only input parameters, allowing access to tabular data without the ability to alter it within the dynamic SQL context.

Here's an example illustrating the use of a TVP:

CREATE TYPE MyTable AS TABLE 
( 
TID int,
RELSku nvarchar(MAX)
);

DECLARE @TSku AS MyTable;

INSERT INTO @TSku VALUES (1,'Item 1'), (2,'Item 2');

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 sp_executesql @sqlstat, N'@TSku MyTable READONLY', @TSku=@TSku;

This revised code showcases:

• A table type MyTable is defined to create the table variable @TSku.
• The dynamic SQL string (@sqlstat) constructs a query that reads data from @TSku without attempting to modify it.
• sp_executesql executes the dynamic SQL, passing @TSku as a READONLY parameter.

This method effectively leverages table-like structures within dynamic SQL in SQL Server 2008, circumventing the inherent limitations of directly manipulating table variables within dynamically generated queries.

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