SQL SELECT 語句SELECT

2023-08-06 06:34:11

SELECT

從資料庫中檢索行，并允許從一個或多個表中選擇一個或多個行或列。雖然 SELECT 語句的完整文法較複雜，但是其主要的子句可歸納如下：

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 ] ]

可以在查詢之間使用 UNION 運算符，以将查詢的結果組合成單個結果集。

SELECT statement ::=

< query_expression >

[ ORDER BY { order_by_expression | column_position [ ASC | DESC ] }

[ 
        ,
              ...n ]

] 
    [ COMPUTE

{

 { AVG | COUNT | MAX | MIN | SUM } 
        (
              expression 
        )

}

 [ 
        ,
              ...n ]
        [ BY expression [ 
        ,
              ...n ]
             ]

] 
    [ FOR { BROWSE | XML { RAW | AUTO | EXPLICIT }

[ 
        ,
              XMLDATA ]

[ 
        ,
               ELEMENTS ]

[ 
        ,
               BINARY base64 ]

}

 
] 
    [ OPTION ( < query_hint > [ 
        ,
              ...n ]) ]

< query expression > ::=

{

 < query specification > | ( < query expression > ) }
    [ UNION [ ALL ] < query specification | ( < query expression > ) [...n ] ]

< query specification > ::=

SELECT [ ALL | DISTINCT ]

[ { TOP integer | TOP integer PERCENT } [ WITH TIES ] ]

< select_list >

[ INTO new_table ]

[ FROM { < table_source > } [ 
        ,
              ...n ] ]

[ WHERE < search_condition > ]

[ GROUP BY [ ALL ] group_by_expression [ 
        ,
              ...n ]

[ WITH { CUBE | ROLLUP } ]

]
    [HAVING <search_condition>]

SQL SELECT 語句SELECT