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@@NESTLEVEL (Transact-SQL)

  • Artikel

Returns the nesting level of the current stored procedure execution (initially 0) on the local server.

Topic link icon Transact-SQL Syntax Conventions

Syntax

@@NESTLEVEL

Return Types

int

Remarks

Each time a stored procedure calls another stored procedure or executes managed code by referencing a common language runtime (CLR) routine, type, or aggregate, the nesting level is incremented. When the maximum of 32 is exceeded, the transaction is terminated.

When @@NESTLEVEL is executed within a Transact-SQL string, the value returned is 1 + the current nesting level. When @@NESTLEVEL is executed dynamically by using sp_executesql the value returned is 2 + the current nesting level.

Examples

A. Using @@NESTLEVEL in a procedure

The following example creates two procedures: one that calls the other, and one that displays the @@NESTLEVEL setting of each.

USE AdventureWorks2012;
GO
IF OBJECT_ID (N'usp_OuterProc', N'P')IS NOT NULL
    DROP PROCEDURE usp_OuterProc;
GO
IF OBJECT_ID (N'usp_InnerProc', N'P')IS NOT NULL
    DROP PROCEDURE usp_InnerProc;
GO
CREATE PROCEDURE usp_InnerProc AS 
    SELECT @@NESTLEVEL AS 'Inner Level';
GO
CREATE PROCEDURE usp_OuterProc AS 
    SELECT @@NESTLEVEL AS 'Outer Level';
    EXEC usp_InnerProc;
GO
EXECUTE usp_OuterProc;
GO

Here is the result set.

Outer Level

-----------

1

Inner Level

-----------

2

B. Calling @@NESTLEVEL

The following example shows the difference in values returned by SELECT, EXEC, and sp_executesql when each of them calls @@NESTLEVEL.

CREATE PROC usp_NestLevelValues AS
    SELECT @@NESTLEVEL AS 'Current Nest Level';
EXEC ('SELECT @@NESTLEVEL AS OneGreater'); 
EXEC sp_executesql N'SELECT @@NESTLEVEL as TwoGreater' ;
GO
EXEC usp_NestLevelValues;
GO

Here is the result set.

Current Nest Level

------------------

1

(1 row(s) affected)

OneGreater

-----------

2

(1 row(s) affected)

TwoGreater

-----------

3

(1 row(s) affected)

See Also

Reference

Configuration Functions (Transact-SQL)

@@TRANCOUNT (Transact-SQL)

Concepts

Create a Stored Procedure