Commands Generating Multiple-Rowset Results
The SQL Server Native Client OLE DB provider can return multiple rowsets from SQL Server statements. SQL Server statements return multiple-rowset results under the following conditions:
Batched SQL statements are submitted as a single command.
Stored procedures implement a batch of SQL statements.
SQL statements include the Transact-SQL COMPUTE or COMPUTE BY clause.
Batches
The SQL Server Native Client OLE DB provider recognizes the semicolon character as a batch delimiter for SQL statements:
WCHAR* wSQLString = L"SELECT * FROM Categories; "
L"SELECT * FROM Products";
Sending multiple SQL statements in one batch is more efficient than executing each SQL statement separately. Sending one batch reduces the network round trips from the client to the server.
Stored Procedures
SQL Server returns a result set for each statement in a stored procedure, so most SQL Server stored procedures return multiple result sets.
COMPUTE BY and COMPUTE
The Transact-SQL COMPUTE BY clause generates subtotals within a SELECT statement result set. The COMPUTE clause generates a total at the end of the result set. The SQL Server Native Client OLE DB provider returns each COMPUTE BY subtotal and the COMPUTE total as a separate rowset result.