描述语言语法的这种语言的名称是什么?
问题描述:
<SELECT statement> ::=
[WITH <common_table_expression> [,...n]]
<query_expression>
[ ORDER BY { order_by_expression | column_position [ ASC | DESC ] }
[ ,...n ] ]
[ COMPUTE
{ { AVG | COUNT | MAX | MIN | SUM } (expression) } [ ,...n ]
[ BY expression [ ,...n ] ]
]
[ <FOR Clause>]
[ OPTION (<query_hint> [ ,...n ]) ]
<query_expression> ::=
{ <query_specification> | (<query_expression>) }
[ { UNION [ ALL ] | EXCEPT | INTERSECT }
<query_specification> | (<query_expression>) [...n ] ]
<query_specification> ::=
SELECT [ ALL | DISTINCT ]
[TOP expression [PERCENT] [ WITH TIES ] ]
<select_list>
[ INTO new_table ]
[ FROM { <table_source> } [ ,...n ] ]
[ WHERE <search_condition> ]
[ <GROUP BY> ]
[ HAVING <search_condition> ]
什么语言叫什么名字?
答
这看起来有点像一部分SQL的BNF定义。
实际上,BNF是通过上下文无关文法定义的,反过来又是一种语言本身。 – pmr 2010-05-21 09:20:47
@pmr - 但是你可以用它编程;) – Oded 2010-05-21 09:22:22