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 insert_statement WHEN NOT MATCHED BY SOURCE THEN DELETE; 首先,在MERGE子句中指定目标表和源表。 其次,m...
通过在 MERGE 语句中指定OPTION (<query_hint>)子句,可以强制使用某种特定联接。 建议不要将哈希联接用作 MERGE 语句的查询提示,因为该联接类型不使用索引。 有关参数化的最佳做法 如果在没有参数的情况下执行 SELECT 、 INSERT 、 UPDATE 或 DELETE 语句, SQL Server 查询优化器可能会选择在内部参数化语句。 也...
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 ...
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。 执行一下上面的 MERGE 语句查看一下结果,两...
Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics SQL database in Microsoft FabricThe 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 ...
SQL Server MERGE Statement 常见问题及解决方法 性能问题:如果 MERGE 语句执行缓慢,可以考虑优化索引、减少数据量或分批处理。 死锁问题:在高并发环境下,MERGE 语句可能导致死锁。可以通过设置事务隔离级别、优化查询顺序或使用锁提示来解决。 数据一致性问题:确保源表和目标表的数据一致性,可以在 MERGE 语句中添加适...
SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics SQL database in Microsoft Fabric The 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, up...
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_tableONmerge_conditionWHENMATCHEDTHENupdate_statementWHEN NOTMATCHEDTHENinsert_statementWHEN NOT MATCHED BYSOURCETHEN DELETE; 首先,在MERGE子句中指定目标表和源表。
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 Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics SQL database in Microsoft Fabric The 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, up...