【13】一个完整的select语句[SELECT (Transact-SQL)]

简介:

从数据库中检索行，并允许从 SQL Server 2012 中的一个或多个表中选择一个或多个行或列。 虽然 SELECT 语句的完整语法较复杂，但其主要子句可归纳如下：

[ WITH <common_table_expression>]

SELECT select_list [ INTO new_table ]

[ FROM table_source ] [ WHERE search_condition ]

[ GROUP BY group_by_expression]

[ HAVING search_condition]

[ ORDER BY order_expression [ ASC | DESC ] ]

可在查询之间使用 UNION、EXCEPT 和 INTERSECT 运算符，以便将各个查询的结果合并或比较到一个结果集中。

语法:

<SELECT statement> ::=
    [WITH <common_table_expression> [,...n]]
    <query_expression>
    [ ORDER BY { order_by_expression | column_position [ ASC | DESC ] }
  [ ,...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 > ]

原文地址：https://www.cnblogs.com/lolitagis02/p/8159433.html