SELECT - Amazon Timestream

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SELECT

SELECT语句可用于从一个或多个表中检索数据。Timestream 的查询语言支持以下语SELECT句语法：

[ WITH with_query [, ...] ]
            SELECT [ ALL | DISTINCT ] select_expr [, ...]
            [ function (expression) OVER (
            [ PARTITION BY partition_expr_list ]
            [ ORDER BY order_list ]
            [ frame_clause ] )
            [ FROM from_item [, ...] ]
            [ WHERE condition ]
            [ GROUP BY [ ALL | DISTINCT ] grouping_element [, ...] ]
            [ HAVING condition]
            [ { UNION | INTERSECT | EXCEPT } [ ALL | DISTINCT ] select ]
            [ ORDER BY order_list ]
            [ LIMIT [ count | ALL ] ]

其中

  • function (expression)是支持的窗口功能之一。

  • partition_expr_list 为：

    expression | column_name [, expr_list ]

  • order_list 为：

    expression | column_name [ ASC | DESC ] 
[ NULLS FIRST | NULLS LAST ]
[, order_list ]

  • frame_clause 为：

    ROWS | RANGE
{ UNBOUNDED PRECEDING | expression PRECEDING | CURRENT ROW } |
{BETWEEN
{ UNBOUNDED PRECEDING | expression { PRECEDING | FOLLOWING } |
CURRENT ROW}
AND
{ UNBOUNDED FOLLOWING | expression { PRECEDING | FOLLOWING } |
CURRENT ROW }}

  • from_item是以下之一：

    table_name [ [ AS ] alias [ ( column_alias [, ...] ) ] ]
from_item join_type from_item [ ON join_condition | USING ( join_column [, ...] ) ]

  • join_type是以下之一：

    [ INNER ] JOIN
LEFT [ OUTER ] JOIN
RIGHT [ OUTER ] JOIN
FULL [ OUTER ] JOIN

  • grouping_element是以下之一：

    ()
expression