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 sourc
For every insert, update, or delete action specified in the MERGE statement, SQL Server fires any corresponding AFTER triggers defined on the target table, but doesn't guarantee on which action to fire triggers first or last. Triggers defined for the same action honor the order you specify....
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SQL Server 2008 中,您可以使用 MERGE 陳述式,在單一陳述式中執行插入、更新或刪除作業。MERGE 陳述式可讓您將資料來源與目標資料表或檢視表進行聯結,然後根據該聯結的結果,針對目標執行多個動作。例如,您可以使用 MERGE 陳述式來執行下列作業: 有條件地在目標資料表中插入或更新資料列。 如果此資料列存在目標資料...
SQL MERGE语句是在SQL Server 2008版中引入的,它为数据库程序员提供了极大的灵活性,可以简化他们在INSERT,UPDATE和DELETE语句周围的混乱代码,同时应用在ETL中实现SCD的逻辑。 (Optimizing the performance of the SQL MERGE statement) There are a few aspects using which you can optimize the performance of your...
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 ; 结束。
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...
‘MERGE’ statement is a new feature in SQL Server 2008. It can be used to perform insert, update and delete operation on a destination table simultaneously based on the results of a join with a source table. Well, it sounds like a bit confusing, but let's see an example on how it ...
SQL コピー 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 ...
EXEC InsertUnitMeasure @UnitMeasureCode = 'ABC', @Name = 'Test Value'; SELECT UnitMeasureCode, Name FROM Production.UnitMeasure WHERE UnitMeasureCode = 'ABC'; GO -- Rewrite the procedure to perform the same operations using the -- MERGE statement. -- Create a temporary table to hold the...