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MERGE

Introduction

Starting with SQL Server 2008, it is possible to perform insert, update, or delete operations in a single statement using the MERGE statement.

The MERGE statement allows you to join a data source with a target table or view, and then perform multiple actions against the target based on the results of that join.

Syntax

  • As per MSDN - https://msdn.microsoft.com/en-us/library/bb510625.aspx [ WITH <common_table_expression> [,...n] ] MERGE [ TOP ( expression ) [ PERCENT ] ] [ INTO ] <target_table> [ WITH ( <merge_hint> ) ] [ [ AS ] table_alias ] USING <table_source> ON <merge_search_condition> [ WHEN MATCHED [ AND <clause_search_condition> ] THEN <merge_matched> ] [ ...n ] [ WHEN NOT MATCHED [ BY TARGET ] [ AND <clause_search_condition> ] THEN <merge_not_matched> ] [ WHEN NOT MATCHED BY SOURCE [ AND <clause_search_condition> ] THEN <merge_matched> ] [ ...n ] [ <output_clause> ] [ OPTION ( <query_hint> [ ,...n ] ) ] ; <target_table> ::= { [ database_name . schema_name . | schema_name . ] target_table } <merge_hint>::= { { [ <table_hint_limited> [ ,...n ] ] [ [ , ] INDEX ( index_val [ ,...n ] ) ] } } <table_source> ::= { table_or_view_name [ [ AS ] table_alias ] [ <tablesample_clause> ] [ WITH ( table_hint [ [ , ]...n ] ) ] | rowset_function [ [ AS ] table_alias ] [ ( bulk_column_alias [ ,...n ] ) ] | user_defined_function [ [ AS ] table_alias ] | OPENXML <openxml_clause> | derived_table [ AS ] table_alias [ ( column_alias [ ,...n ] ) ] | <joined_table> | <pivoted_table> | <unpivoted_table> } <merge_search_condition> ::= <search_condition> <merge_matched>::= { UPDATE SET <set_clause> | DELETE } <set_clause>::= SET { column_name = { expression | DEFAULT | NULL } | { udt_column_name.{ { property_name = expression | field_name = expression } | method_name ( argument [ ,...n ] ) } } | column_name { .WRITE ( expression , @Offset , @Length ) } | @variable = expression | @variable = column = expression | column_name { += | -= | *= | /= | %= | &= | ^= | |= } expression | @variable { += | -= | *= | /= | %= | &= | ^= | |= } expression | @variable = column { += | -= | *= | /= | %= | &= | ^= | |= } expression } [ ,...n ] <merge_not_matched>::= { INSERT [ ( column_list ) ] { VALUES ( values_list ) | DEFAULT VALUES } } <clause_search_condition> ::= <search_condition> ::= { [ NOT ] | ( <search_condition> ) } [ { AND | OR } [ NOT ] { | ( <search_condition> ) } ] [ ,...n ] ::= { expression { = | < > | ! = |

    | > = | ! > | < | < = | ! < } expression | string_expression [ NOT ] LIKE string_expression [ ESCAPE 'escape_character' ] | expression [ NOT ] BETWEEN expression AND expression | expression IS [ NOT ] NULL | CONTAINS ( { column | * } , '< contains_search_condition >' ) | FREETEXT ( { column | * } , 'freetext_string' ) | expression [ NOT ] IN ( subquery | expression [ ,...n ] ) | expression { = | < > | ! = | | > = | ! > | < | < = | ! < } { ALL | SOME | ANY} ( subquery ) | EXISTS ( subquery ) } <output_clause>::= { [ OUTPUT <dml_select_list> INTO { @table_variable | output_table } [ (column_list) ] ] [ OUTPUT <dml_select_list> ] } <dml_select_list>::= { <column_name> | scalar_expression } [ [AS] column_alias_identifier ] [ ,...n ] <column_name> ::= { DELETED | INSERTED | from_table_name } . { * | column_name } | $action

Remarks

Performs insert, update, or delete operations on a target table based on the results of a join with a source table. For example, you can synchronize two tables by inserting, updating, or deleting rows in one table based on differences found in the other table.

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