DROP STATISTICS (Transact-SQL)

Άρθρο
09/03/2024

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

Drops statistics for multiple collections within the specified tables in the current database.

Note

For more information on statistics in Microsoft Fabric, see Statistics in Microsoft Fabric.

Transact-SQL syntax conventions

Syntax

-- Syntax for SQL Server and Azure SQL Database  
  
DROP STATISTICS table.statistics_name | view.statistics_name [ ,...n ]

-- Syntax for Azure Synapse Analytics and Parallel Data Warehouse and Microsoft Fabric
  
DROP STATISTICS [ schema_name . ] table_name.statistics_name   
[;]

Arguments

table | view
Is the name of the target table or indexed view for which statistics should be dropped. Table and view names must comply with the rules for Database Identifiers. Specifying the table or view owner name is optional.

statistics_name
Is the name of the statistics group to drop. Statistics names must comply with the rules for identifiers

Remarks

Be careful when you drop statistics. Doing so may affect the execution plan chosen by the query optimizer.

Statistics on indexes cannot be dropped by using DROP STATISTICS. Statistics remain as long as the index exists.

For more information about displaying statistics, see DBCC SHOW_STATISTICS (Transact-SQL).

Permissions

Requires ALTER permission on the table or view.

Examples

A. Dropping statistics from a table

The following example drops the statistics groups (collections) of two tables. The VendorCredit statistics group (collection) of the Vendor table and the CustomerTotal statistics (collection) of the SalesOrderHeader table are dropped.

-- Create the statistics groups.  
USE AdventureWorks2022;  
GO  
CREATE STATISTICS VendorCredit  
    ON Purchasing.Vendor (Name, CreditRating)  
    WITH SAMPLE 50 PERCENT  
CREATE STATISTICS CustomerTotal  
    ON Sales.SalesOrderHeader (CustomerID, TotalDue)  
    WITH FULLSCAN;  
GO  
DROP STATISTICS Purchasing.Vendor.VendorCredit, Sales.SalesOrderHeader.CustomerTotal;

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

B. Dropping statistics from a table

The following examples drop the CustomerStats1 statistics from table Customer.

DROP STATISTICS Customer.CustomerStats1;  
DROP STATISTICS dbo.Customer.CustomerStats1;

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