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option-clause-transact-sql.md

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title OPTION Clause (Transact-SQL)
description OPTION Clause (Transact-SQL)
author VanMSFT
ms.author vanto
ms.reviewer wiassaf
ms.date 04/17/2024
ms.service sql
ms.subservice t-sql
ms.topic reference
f1_keywords
OPTION clause
OPTION_TSQL
OPTION
OPTION_clause_TSQL
helpviewer_keywords
clauses [SQL Server], OPTION
OPTION clause
dev_langs
TSQL
ms.custom
build-2024
monikerRange >=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-server-2016||>=sql-server-linux-2017||=azuresqldb-mi-current||=fabric

OPTION Clause (Transact-SQL)

[!INCLUDE sql-asdb-asdbmi-asa-pdw-fabricse-fabricdw]

Specifies that the indicated query hint should be used throughout the entire query. Each query hint can be specified only one time, although multiple query hints are permitted. Only one OPTION clause can be specified with the statement.

This clause can be specified in the SELECT, DELETE, UPDATE, and MERGE statements.

:::image type="icon" source="../../includes/media/topic-link-icon.svg" border="false"::: Transact-SQL syntax conventions

Syntax

Syntax for [!INCLUDE ssnoversion-md.md] and [!INCLUDE ssazure-sqldb]

[ OPTION ( <query_hint> [ ,...n ] ) ]

Syntax for [!INCLUDE fabric-dw] in [!INCLUDE fabric]

OPTION ( <query_option> [ ,...n ] )  
  
<query_option> ::=  
    LABEL = label_name |  
    <query_hint>  
  
<query_hint> ::=  
    HASH JOIN   
    | LOOP JOIN   
    | MERGE JOIN  
    | FORCE ORDER  
    | { FORCE | DISABLE } EXTERNALPUSHDOWN  
    | FOR TIMESTAMP AS OF '<point_in_time>'

Syntax for [!INCLUDE ssazuresynapse-md.md] and [!INCLUDE sspdw-md.md] and [!INCLUDE fabric-dw] in [!INCLUDE fabric]

OPTION ( <query_option> [ ,...n ] )  
  
<query_option> ::=  
    LABEL = label_name |  
    <query_hint>  
  
<query_hint> ::=  
    HASH JOIN   
    | LOOP JOIN   
    | MERGE JOIN  
    | FORCE ORDER  
    | { FORCE | DISABLE } EXTERNALPUSHDOWN

Syntax for [!INCLUDE sssodfull-md.md]

OPTION ( <query_option> [ ,...n ] )

<query_option> ::=
    LABEL = label_name

[!INCLUDE sql-server-tsql-previous-offline-documentation]

Arguments

query_hint

Keywords that indicate which optimizer hints are used to customize the way the Database Engine processes the statement. For more information, see Query Hints (Transact-SQL).

Examples

A. Use an OPTION clause with a GROUP BY clause

The following example shows how the OPTION clause is used with a GROUP BY clause.

USE AdventureWorks2022;  
GO  
SELECT ProductID, OrderQty, SUM(LineTotal) AS Total  
FROM Sales.SalesOrderDetail  
WHERE UnitPrice < $5.00  
GROUP BY ProductID, OrderQty  
ORDER BY ProductID, OrderQty  
OPTION (HASH GROUP, FAST 10);  
GO

Examples: [!INCLUDE ssazuresynapse-md] and [!INCLUDE ssPDW]

B. SELECT statement with a label in the OPTION clause

The following example shows an [!INCLUDE ssazuresynapse-md] SELECT statement with a label in the OPTION clause.

-- Uses AdventureWorks  
  
SELECT * FROM FactResellerSales  
  OPTION ( LABEL = 'q17' );

C. SELECT statement with a query hint in the OPTION clause

The following example shows a SELECT statement that uses a HASH JOIN query hint in the OPTION clause.

-- Uses AdventureWorks  
  
SELECT COUNT (*) FROM dbo.DimCustomer a  
INNER JOIN dbo.FactInternetSales b   
ON (a.CustomerKey = b.CustomerKey)  
OPTION (HASH JOIN);

D. SELECT statement with a label and multiple query hints in the OPTION clause

The following example is a [!INCLUDE ssazuresynapse-md] SELECT statement that contains a label and multiple query hints. When the query is run on the Compute nodes, [!INCLUDE ssNoVersion] will apply a hash join or merge join, according to the strategy that [!INCLUDE ssNoVersion] decides is the most optimal.

-- Uses AdventureWorks  
  
SELECT COUNT (*) FROM dbo.DimCustomer a  
INNER JOIN dbo.FactInternetSales b   
ON (a.CustomerKey = b.CustomerKey)  
OPTION ( Label = 'CustJoin', HASH JOIN, MERGE JOIN);

E. Use a query hint when querying a view

The following example creates a view named CustomerView and then uses a HASH JOIN query hint in a query that references a view and a table.

-- Uses the AdventureWorks sample database
  
CREATE VIEW CustomerView  
AS  
SELECT CustomerKey, FirstName, LastName FROM ssawPDW..DimCustomer;  
GO
SELECT COUNT (*) FROM dbo.CustomerView a  
INNER JOIN dbo.FactInternetSales b  
ON (a.CustomerKey = b.CustomerKey)  
OPTION (HASH JOIN);  
GO
DROP VIEW CustomerView;
GO

F. Query with a subselect and a query hint

The following example shows a query that contains both a subselect and a query hint. The query hint is applied globally. Query hints are not allowed to be appended to the subselect statement.

-- Uses the AdventureWorks sample database
CREATE VIEW CustomerView AS  
SELECT CustomerKey, FirstName, LastName FROM ssawPDW..DimCustomer;  
GO
SELECT * FROM (  
SELECT COUNT (*) AS a FROM dbo.CustomerView a  
INNER JOIN dbo.FactInternetSales b  
ON ( a.CustomerKey = b.CustomerKey )) AS t  
OPTION (HASH JOIN);

G. Force the join order to match the order in the query

The following example uses the FORCE ORDER hint to force the query plan to use the join order specified by the query. This will improve performance on some queries; not all queries.

-- Uses AdventureWorks  
  
-- Obtain partition numbers, boundary values, boundary value types, and rows per boundary  
-- for the partitions in the ProspectiveBuyer table of the ssawPDW database.  
SELECT sp.partition_number, prv.value AS boundary_value, lower(sty.name) AS boundary_value_type, sp.rows   
FROM sys.tables st JOIN sys.indexes si ON st.object_id = si.object_id AND si.index_id <2  
JOIN sys.partitions sp ON sp.object_id = st.object_id AND sp.index_id = si.index_id  
JOIN sys.partition_schemes ps ON ps.data_space_id = si.data_space_id   
JOIN sys.partition_range_values prv ON prv.function_id = ps.function_id   
JOIN sys.partition_parameters pp ON pp.function_id = ps.function_id   
JOIN sys.types sty ON sty.user_type_id = pp.user_type_id AND prv.boundary_id = sp.partition_number   
WHERE st.object_id = (SELECT object_id FROM sys.objects WHERE name = 'FactResellerSales')   
ORDER BY sp.partition_number  
OPTION ( FORCE ORDER )  
;

H. Use EXTERNALPUSHDOWN

The following example forces the pushdown of the WHERE clause to the MapReduce job on the external Hadoop table.

SELECT ID FROM External_Table_AS A   
WHERE ID < 1000000  
OPTION (FORCE EXTERNALPUSHDOWN);

The following example prevents the pushdown of the WHERE clause to the MapReduce job on the external Hadoop table. All rows are returned to PDW where the WHERE clause is applied.

SELECT ID FROM External_Table_AS A   
WHERE ID < 10  
OPTION (DISABLE EXTERNALPUSHDOWN);

I. Query data as of a point in time

Applies to: [!INCLUDE fabric-dw] in [!INCLUDE fabric]

For more information, see FOR TIMESTAMP query hint.

Use the TIMESTAMP syntax in the OPTION clause to query data as it existed in the past, in Synapse Data Warehouse in Microsoft Fabric. The following sample query returns data as it appeared on March 13, 2024 at 7:39:35.28 PM UTC. The time zone is always in UTC.

SELECT OrderDateKey, SUM(SalesAmount) AS TotalSales
FROM FactInternetSales
GROUP BY OrderDateKey
ORDER BY OrderDateKey
OPTION (FOR TIMESTAMP AS OF '2024-03-13T19:39:35.28'); --March 13, 2024 at 7:39:35.28 PM UTC

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