如果使用INSERT,UPDATE以及DELETE单独的语句,你必须建立三个单独的语句从源表匹配的行更新数据到目标表。 但是,SQL Server提供了MERGE允许同时执行三个操作的语句。下面显示了该MERGE语句的语法: MERGE target_table USING source_table ON merge_condition WHEN MATCHED THEN update_statement WHEN NOT MATCHED THEN inse...
在Merge Not Matched 操作中,只允许执行 INSERT 语句。 一个Merge 语句中出现的 Matched 操作,只能出现一次 UPDATE 或者 DELETE 语句,否则就会出现下面的错误 -An action of type 'WHEN MATCHED' cannot appear more than once in a 'UPDATE' clause of a MERGE statement. Merge 语句最后必须包含分号,以 ; 结...
Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse AnalyticsThe MERGE statement runs insert, update, or delete operations on a target table from the results of a join with a source table. For example, synchronize two tables by inserting, updating, or deleting ...
SQL Copiar CREATE PROCEDURE dbo.InsertUnitMeasure @UnitMeasureCode NCHAR(3), @Name NVARCHAR(25) AS BEGIN SET NOCOUNT ON; -- Update the row if it exists. UPDATE Production.UnitMeasure SET Name = @Name WHERE UnitMeasureCode = @UnitMeasureCode -- Insert the row if the UPDATE statement ...
When you run a merge statement in Microsoft SQL Server, a deadlock condition may occur between the merge operation and a background thread on the Clustered Columnstore Index (CCI) table. However, SQL Server does not detect the deadlock. ...
當您在 Microsoft SQL Server 中執行 merge 語句時,可能會在合併作業與聚集列存儲索引(CCI)資料表的背景執行緒之間發生鎖死情況。不過,SQL Server 不會偵測到鎖死。 注意事項 如果啟用追蹤標記1222,就會記錄 N o 錯誤報表。 如果您使用XEvent 記錄來捕...
MERGE INTO 语句是 SQL Server 中一个强大的工具,用于在一个操作中同时完成插入、更新和删除操作。然而,不当的使用可能会导致性能问题。本文将详细介绍如何优化 MERGE INTO 语句,包括索引优化、批处理、事务管理等方面,并提供相应的代码示例。 1. 基本语法 ...
SQL 複製 CREATE PROCEDURE dbo.InsertUnitMeasure @UnitMeasureCode NCHAR(3), @Name NVARCHAR(25) AS BEGIN SET NOCOUNT ON; -- Update the row if it exists. UPDATE Production.UnitMeasure SET Name = @Name WHERE UnitMeasureCode = @UnitMeasureCode -- Insert the row if the UPDATE statement ...
SQL 複製 CREATE PROCEDURE dbo.InsertUnitMeasure @UnitMeasureCode NCHAR(3), @Name NVARCHAR(25) AS BEGIN SET NOCOUNT ON; -- Update the row if it exists. UPDATE Production.UnitMeasure SET Name = @Name WHERE UnitMeasureCode = @UnitMeasureCode -- Insert the row if the UPDATE statement ...
SQL CREATEPROCEDUREdbo.InsertUnitMeasure @UnitMeasureCodeNCHAR(3), @NameNVARCHAR(25)ASBEGINSETNOCOUNTON;-- Update the row if it exists.UPDATEProduction.UnitMeasureSETName= @NameWHEREUnitMeasureCode = @UnitMeasureCode-- Insert the row if the UPDATE statement failed.IF(@@ROWCOUNT =0)BEGININSERTINT...