sp_executesql (Transact-SQL)

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW) SQL analytics endpoint in Microsoft Fabric Warehouse in Microsoft Fabric

Executes a Transact-SQL statement or batch that can be reused many times, or one that is built dynamically. The Transact-SQL statement or batch can contain embedded parameters.

Caution

Runtime-compiled Transact-SQL statements can expose applications to malicious attacks. You should parameterize your queries when using sp_executesql. For more information, see SQL injection.

Transact-SQL syntax conventions

Syntax

Syntax for SQL Server, Azure SQL Database, Azure SQL Managed Instance, Azure Synapse Analytics, and Analytics Platform System (PDW).

sp_executesql [ @stmt = ] N'statement'
[
    [ , [ @params = ] N'@parameter_name data_type [ { OUT | OUTPUT } ] [ , ...n ]' ]
    [ , [ @param1 = ] 'value1' [ , ...n ] ]
]

The Transact-SQL code samples in this article use the AdventureWorks2022 or AdventureWorksDW2022 sample database, which you can download from the Microsoft SQL Server Samples and Community Projects home page.

Arguments

[ @stmt = ] N'statement'

A Unicode string that contains a Transact-SQL statement or batch. @stmt must be either a Unicode constant or a Unicode variable. More complex Unicode expressions, such as concatenating two strings with the + operator, aren't allowed. Character constants aren't allowed. Unicode constants must be prefixed with an N. For example, the Unicode constant N'sp_who' is valid, but the character constant 'sp_who' isn't. The size of the string is limited only by available database server memory. On 64-bit servers, the size of the string is limited to 2 GB, the maximum size of nvarchar(max).

@stmt can contain parameters having the same form as a variable name. For example:

N'SELECT * FROM HumanResources.Employee WHERE EmployeeID = @IDParameter';

Each parameter included in @stmt must have a corresponding entry in both the @params parameter definition list and the parameter values list.

[ @params = ] N'@parameter_name data_type [ , ...n ]'

A string that contains the definitions of all parameters that are embedded in @stmt. The string must be either a Unicode constant or a Unicode variable. Each parameter definition consists of a parameter name and a data type. n is a placeholder that indicates more parameter definitions. Every parameter specified in @stmt must be defined in @params. If the Transact-SQL statement or batch in @stmt doesn't contain parameters, @params isn't required. The default value for this parameter is NULL.

[ @param1 = ] 'value1'

A value for the first parameter that is defined in the parameter string. The value can be a Unicode constant or a Unicode variable. There must be a parameter value supplied for every parameter included in @stmt. The values aren't required when the Transact-SQL statement or batch in @stmt has no parameters.

{ OUT | OUTPUT }

Indicates that the parameter is an output parameter. text, ntext, and image parameters can be used as OUTPUT parameters, unless the procedure is a common language runtime (CLR) procedure. An output parameter that uses the OUTPUT keyword can be a cursor placeholder, unless the procedure is a CLR procedure.

[ ... n ]

A placeholder for the values of extra parameters. Values can only be constants or variables. Values can't be more complex expressions such as functions, or expressions built by using operators.

Return code values

0 (success) or non-zero (failure).

Result set

Returns the result sets from all the SQL statements built into the SQL string.

Remarks

sp_executesql parameters must be entered in the specific order as described in the Syntax section earlier in this article. If the parameters are entered out of order, an error message occurs.

sp_executesql has the same behavior as EXECUTE regarding batches, the scope of names, and database context. The Transact-SQL statement or batch in the sp_executesql @stmt parameter isn't compiled until the sp_executesql statement is executed. The contents of @stmt are then compiled and executed as an execution plan separate from the execution plan of the batch that called sp_executesql. The sp_executesql batch can't reference variables declared in the batch that calls sp_executesql. Local cursors or variables in the sp_executesql batch aren't visible to the batch that calls sp_executesql. Changes in database context last only to the end of the sp_executesql statement.

sp_executesql can be used instead of stored procedures to execute a Transact-SQL statement many times when the change in parameter values to the statement is the only variation. Because the Transact-SQL statement itself remains constant and only the parameter values change, the SQL Server query optimizer is likely to reuse the execution plan it generates for the first execution. In this scenario, performance is equivalent to that of a stored procedure.

Note

To improve performance, use fully qualified object names in the statement string.

sp_executesql supports the setting of parameter values separately from the Transact-SQL string, as shown in the following example.

DECLARE @IntVariable AS INT;
DECLARE @SQLString AS NVARCHAR (500);
DECLARE @ParmDefinition AS NVARCHAR (500);

/* Build the SQL string once */
SET @SQLString = N'SELECT BusinessEntityID, NationalIDNumber, JobTitle, LoginID
       FROM AdventureWorks2022.HumanResources.Employee
       WHERE BusinessEntityID = @BusinessEntityID';

SET @ParmDefinition = N'@BusinessEntityID tinyint';

/* Execute the string with the first parameter value. */
SET @IntVariable = 197;

EXECUTE sp_executesql
    @SQLString,
    @ParmDefinition,
    @BusinessEntityID = @IntVariable;

/* Execute the same string with the second parameter value. */
SET @IntVariable = 109;

EXECUTE sp_executesql
    @SQLString,
    @ParmDefinition,
    @BusinessEntityID = @IntVariable;

Output parameters can also be used with sp_executesql. The following example retrieves a job title from the HumanResources.Employee table in the AdventureWorks2022 sample database, and returns it in the output parameter @max_title.

DECLARE @IntVariable AS INT;

DECLARE @SQLString AS NVARCHAR (500);

DECLARE @ParmDefinition AS NVARCHAR (500);

DECLARE @max_title AS VARCHAR (30);

SET @IntVariable = 197;

SET @SQLString = N'SELECT @max_titleOUT = max(JobTitle)
   FROM AdventureWorks2022.HumanResources.Employee
   WHERE BusinessEntityID = @level';

SET @ParmDefinition = N'@level TINYINT, @max_titleOUT VARCHAR(30) OUTPUT';

EXECUTE sp_executesql
    @SQLString,
    @ParmDefinition,
    @level = @IntVariable,
    @max_titleOUT = @max_title OUTPUT;

SELECT @max_title;

Being able to substitute parameters in sp_executesql offers the following advantages over using the EXECUTE statement to execute a string:

• Because the actual text of the Transact-SQL statement in the sp_executesql string doesn't change between executions, the query optimizer probably matches the Transact-SQL statement in the second execution with the execution plan generated for the first execution. Therefore, SQL Server doesn't have to compile the second statement.

• The Transact-SQL string is built only once.

• The integer parameter is specified in its native format. Casting to Unicode isn't required.

OPTIMIZED_SP_EXECUTESQL

Applies to: Azure SQL Database

When the OPTIMIZED_SP_EXECUTESQL database scoped configuration is enabled, the compilation behavior of batches submitted using sp_executesql becomes identical to the serialized compilation behavior that objects such as stored procedures and triggers currently employ.

When batches are identical (excluding any parameter differences), the OPTIMIZED_SP_EXECUTESQL option tries to obtain a compile lock as an enforcement mechanism to guarantee that the compilation process is serialized. This lock ensures that if multiple sessions invoke sp_executesql simultaneously, those sessions will wait while trying to obtain an exclusive compile lock after the first session starts the compilation process. The first execution of sp_executesql compiles and inserts its compiled plan into the plan cache. Other sessions abort waiting on the compile lock and reuse the plan once it becomes available.

Without the OPTIMIZED_SP_EXECUTESQL option, multiple invocations of identical batches executed via sp_executesql compile in parallel and place their own copies of a compiled plan into the plan cache, which replace or duplicate plan cache entries in some cases.

Note

Before you enable the OPTIMIZED_SP_EXECUTESQL database scoped configuration, if automatic update statistics is enabled, you should also enable the auto update statistics asynchronous option with the ASYNC_STATS_UPDATE_WAIT_AT_LOW_PRIORITY database scoped configuration option. Enabling these two options can significantly reduce the probability that performance issues related to long compilation times along with excessive, lock manager exclusive locks (LCK_M_X) and WAIT_ON_SYNC_STATISTICS_REFRESH waits.

OPTIMIZED_SP_EXECUTESQL is off by default. To enable OPTIMIZED_SP_EXECUTESQL at the database level, use the following Transact-SQL statement:

ALTER DATABASE SCOPED CONFIGURATION
SET OPTIMIZED_SP_EXECUTESQL = ON;

Permissions

Requires membership in the public role.

Examples

A. Execute a SELECT statement

The following example creates and executes a SELECT statement that contains an embedded parameter named @level.

EXECUTE sp_executesql
    N'SELECT * FROM AdventureWorks2022.HumanResources.Employee
    WHERE BusinessEntityID = @level',
    N'@level TINYINT',
    @level = 109;

B. Execute a dynamically built string

The following example shows using sp_executesql to execute a dynamically built string. The example stored procedure is used to insert data into a set of tables that are used to partition sales data for a year. There's one table for each month of the year that has the following format:

CREATE TABLE May1998Sales
(
    OrderID INT PRIMARY KEY,
    CustomerID INT NOT NULL,
    OrderDate DATETIME NULL CHECK (DATEPART(yy, OrderDate) = 1998),
    OrderMonth INT CHECK (OrderMonth = 5),
    DeliveryDate DATETIME NULL,
    CHECK (DATEPART(mm, OrderDate) = OrderMonth)
);

This sample stored procedure dynamically builds and executes an INSERT statement to insert new orders into the correct table. The example uses the order date to build the name of the table that should contain the data, and then incorporates that name into an INSERT statement.

Note

This is a basic example for sp_executesql. The example doesn't contain error checking, and doesn't include checks for business rules, such as guaranteeing that order numbers aren't duplicated between tables.

CREATE PROCEDURE InsertSales @PrmOrderID INT,
    @PrmCustomerID INT,
    @PrmOrderDate DATETIME,
    @PrmDeliveryDate DATETIME
AS
DECLARE @InsertString AS NVARCHAR (500);
DECLARE @OrderMonth AS INT;
-- Build the INSERT statement.
SET @InsertString = 'INSERT INTO ' +
    /* Build the name of the table. */
    SUBSTRING(DATENAME(mm, @PrmOrderDate), 1, 3) +
    CAST(DATEPART(yy, @PrmOrderDate) AS CHAR(4)) + 'Sales' +
    /* Build a VALUES clause. */
    ' VALUES (@InsOrderID, @InsCustID, @InsOrdDate,' +
    ' @InsOrdMonth, @InsDelDate)';

/* Set the value to use for the order month because
   functions are not allowed in the sp_executesql parameter
   list. */
SET @OrderMonth = DATEPART(mm, @PrmOrderDate);

EXEC sp_executesql @InsertString,
    N'@InsOrderID INT, @InsCustID INT, @InsOrdDate DATETIME,
       @InsOrdMonth INT, @InsDelDate DATETIME',
    @PrmOrderID,
    @PrmCustomerID,
    @PrmOrderDate,
    @OrderMonth,
    @PrmDeliveryDate;
GO

Using sp_executesql in this procedure is more efficient than using EXECUTE to execute the dynamically built string, because it allows for the use of parameter markers. Parameter markers make it more likely that the Database Engine reuses the generated query plan, which helps to avoid additional query compilations. With EXECUTE, each INSERT string is unique because the parameter values are different, and would be appended to the end of the dynamically generated string. When executed, the query wouldn't be parameterized in a way that encourages plan reuse, and would have to be compiled before each INSERT statement is executed, which would add a separate cached entry of the query in the plan cache.

C. Use the OUTPUT parameter

The following example uses an OUTPUT parameter to store the result set generated by the SELECT statement in the @SQLString parameter. Two SELECT statements are then executed that use the value of the OUTPUT parameter.

USE AdventureWorks2022;
GO

DECLARE @SQLString AS NVARCHAR (500);
DECLARE @ParmDefinition AS NVARCHAR (500);
DECLARE @SalesOrderNumber AS NVARCHAR (25);
DECLARE @IntVariable AS INT;

SET @SQLString = N'SELECT @SalesOrderOUT = MAX(SalesOrderNumber)
    FROM Sales.SalesOrderHeader
    WHERE CustomerID = @CustomerID';

SET @ParmDefinition = N'@CustomerID INT,
    @SalesOrderOUT NVARCHAR(25) OUTPUT';

SET @IntVariable = 22276;

EXECUTE sp_executesql
    @SQLString,
    @ParmDefinition,
    @CustomerID = @IntVariable,
    @SalesOrderOUT = @SalesOrderNumber OUTPUT;

-- This SELECT statement returns the value of the OUTPUT parameter.
SELECT @SalesOrderNumber;

-- This SELECT statement uses the value of the OUTPUT parameter in
-- the WHERE clause.
SELECT OrderDate,
       TotalDue
FROM Sales.SalesOrderHeader
WHERE SalesOrderNumber = @SalesOrderNumber;

Examples: Azure Synapse Analytics and Analytics Platform System (PDW)

D. Execute a SELECT statement

The following example creates and executes a SELECT statement that contains an embedded parameter named @level.

EXECUTE sp_executesql
    N'SELECT * FROM AdventureWorksPDW2012.dbo.DimEmployee
    WHERE EmployeeKey = @level',
    N'@level TINYINT',
    @level = 109;

Related content

• EXECUTE (Transact-SQL)
• System stored procedures (Transact-SQL)