Book Image

SQL Server 2014 Development Essentials

By : Basit A. Masood-Al-Farooq
Book Image

SQL Server 2014 Development Essentials

By: Basit A. Masood-Al-Farooq

Overview of this book

Table of Contents (14 chapters)
SQL Server 2014 Development Essentials
About the Author
About the Reviewers

Using the MERGE statement

In SQL Server, you can perform multiple DML operations in a single code block using the MERGE statement. The MERGE statement is a powerful Transact-SQL language feature that allows you to join a source table with a target table, and then perform multiple DML operations against the specified target table, based on the results of the MERGE statement join conditions. By using a MERGE statement, you can improve the performance of OLTP applications, since the data is processed only once.

To execute a MERGE statement, a user must at least have a SELECT permission assigned on the source table and INSERT, UPDATE, and DELETE permissions assigned on the target table.

The basic syntax for the MERGE statement is as follows:

[ WITH <common_table_expression> [,...n] ]
    [ TOP ( expression ) [ PERCENT ] ]
    [ INTO ] <target_table> [ WITH ( <merge_hint> ) ]
    USING <source_table>
    ON <merge_search_condition>
    [ WHEN MATCHED [ AND &lt...