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作者:豆豆网 来源:豆豆网 2008年1月29日
MERGE 的语法为:
[ WITH <common_table_expression> [,...n] ]
MERGE
[ TOP ( expression ) [ PERCENT ] ]
[ INTO ] target_table [ [ AS ] table_alias ]
[ WITH ( <merge_hint> ) ]
USING <table_source>
ON <search_condition>
[ WHEN MATCHED [ AND <search_condition> ]
THEN <merge_matched> ]
[ WHEN [TARGET] NOT MATCHED [ AND <search_condition> ]
THEN <merge_not_matched> ]
[ WHEN SOURCE NOT MATCHED [ AND <search_condition> ]
THEN <merge_ matched> ]
<output_clause>
[ OPTION ( <query_hint> [ ,...n ] ) ]
;
<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_matched>::=
{ UPDATE SET <set_clause> | DELETE }
<set_clause>::=
{ 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
} [ ,...n ]
<merge_not_matched>::=
INSERT [ ( <column_list> ) ]
{ VALUES ( <values_list> )
| DEFAULT VALUES }
<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
示例:在一条 SQL 语句中使用 WHERE 在一张表上执行 UPDATE 和 DELETE 操作
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