How Can I Dynamically Insert Table Variables into SQL Statements in SQL Server 2008 ?

Integrating Table Variables into Dynamic SQL in SQL Server 2008 and Later

Building dynamic SQL queries in SQL Server 2008 and later versions often requires incorporating table variables. Directly including them, however, frequently results in "undeclared table variable" errors.

The solution lies in leveraging table-valued parameters. These parameters enable the passing of table variables into dynamic SQL without modifying the base tables.

Let's examine a common problem:

<code class="language-sql">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);</code>

This code will fail because @RelPro and @TSku are not recognized within the dynamic SQL context. To correctly pass @TSku, utilize a table-valued parameter:

<code class="language-sql">EXEC sp_executesql
  N'SELECT * FROM @T',
  N'@T MyTable READONLY',
  @T=@TSku;</code>

Here, @TSku is passed as a read-only parameter (READONLY) to sp_executesql. The @T parameter acts as a placeholder within the dynamic SQL statement. This method cleanly integrates table variables into your dynamic queries, preventing declaration errors and ensuring smooth execution. This approach provides a robust and efficient way to manage dynamic SQL queries involving table variables.

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