如何看懂SQL Server语法表达式
发现我看不懂语法，晕死了！
比如下面这个表达式：
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[ 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 ] ) ]  

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“[]”区域一般表示什么，“<>”什么意思，“()”什么意思，“...”什么意思。
最好把上面的语法示例翻译下给我，谢谢大侠们！！



------解决方案--------------------
联机帮助上写得很清楚的
http://msdn.microsoft.com/zh-cn/library/ms177563.aspx