BEGIN...END (Transact-SQL)

{ sql_statement| statement_block }

Is any valid Transact-SQL statement or statement grouping as defined by using a statement block.

BEGIN...END blocks can be nested.

Although all Transact-SQL statements are valid within a BEGIN...END block, certain Transact-SQL statements should not be grouped together within the same batch, or statement block.

In the following example, BEGIN and END define a series of Transact-SQL statements that execute together. If the BEGIN...END block were not included, both ROLLBACK TRANSACTION statements would execute and both PRINT messages would be returned.

USE AdventureWorks2012;
GO
BEGIN TRANSACTION;
GO
IF @@TRANCOUNT = 0
BEGIN
    SELECT FirstName, MiddleName 
    FROM Person.Person WHERE LastName = 'Adams';
    ROLLBACK TRANSACTION;
    PRINT N'Rolling back the transaction two times would cause an error.';
END;
ROLLBACK TRANSACTION;
PRINT N'Rolled back the transaction.';
GO
/*
Rolled back the transaction.
*/

Reference