格式的文件并指定压缩算法为snappy SELECT * FROM t1 into outfile 'data1.parquet' format = (TYPE = 'PARQUET' COMPRESSION = 'SNAPPY'); -- 将t1表导出为Parquet格式的文件并指定row_group大小为128MB SELECT * FROM t1 into outfile 'data1.p
文档中心 OceanBase 数据库企业版 SQL 型 V3.2.4 使用指南 性能调优 SQL 调优指南 SQL 执行计划 执行计划算子 SELECT INTO 更新时间:2025-03-10 23:00:01 SELECT INTO算子用于将查询结果赋值给变量列表,查询仅返回一行数据。 如下示例查询中,SELECT输出列为COUNT(*)和MAX(c1),其查询结果分别赋值给变量@a和@b...
SQLTOP, LIMIT, FETCH FIRST or ROWNUMClause ❮ PreviousNext ❯ The SQL SELECT TOP Clause TheSELECT TOPclause is used to specify the number of records to return. TheSELECT TOPclause is useful on large tables with thousands of records. Returning a large number of records can impact performanc...
1.使用row_number()函数进行编号,如 select email,customerID, ROW_NUMBER() over(order by psd) as rows from QT_Customer 原理:先按psd进行排序,排序完后,给每条数据进行编号。 2.在订单中按价格的升序进行排序,并给每条记录进行排序代码如下: select DID,customerID,totalPrice,ROW_NUMBER() over(order by...
使用SQL Server 2005 独有的 ROW_NUMBER() OVER () 语法 搭配CTE (一般数据表表达式,就是 WITH 那段语法)选取序号 2 ~ 4 的数据 */ WITH 排序后的图书 AS (SELECT ROW_NUMBER()OVER(ORDERBY 客户编号 DESC)AS 序号 , 客户编号 , 公司名称
如果您使用的是按需付费模式,则导致费用增加;如果您使用包年包月付费模式,则会导致SQL计算性能下降。 命令格式 [WITH <cte>[, ...] ] SELECT [ALL | DISTINCT] <SELECT_expr>[, <EXCEPT_expr>][, <REPLACE_expr>] ... FROM <TABLE_reference> [WHERE <WHERE_condition>] [GROUP BY {<col_list>|...
Query OK,1row affected Rows matched:1Changed:1Warnings:0 在会话 1中执行如下语句,查询更新后的数据。 SELECT*FROMfruit_orderWHEREorder_id=7; 返回结果如下: +---+---+---+---+---+|order_id|user_id|user_name|fruit_price|order_year|+---+---+---+---+---+|7|1022|李四|16.15...
SQL Copy SELECT OrderDateKey, SUM(SalesAmount) AS TotalSales FROM FactInternetSales GROUP BY OrderDateKey ORDER BY OrderDateKey; Because of the GROUP BY clause, only one row containing the sum of all sales is returned for each day. E. Use GROUP BY with multiple groups The following ex...
[ ASC | DESC | USING operator ]|nlssort_expression_clause][ NULLS { FIRST | LAST } ]}[, ...]][ { [ LIMIT { count | ALL } ][ OFFSET start [ ROW | ROWS ]] } | {LIMITstart, {count|ALL} } ][ FETCH { FIRST | NEXT } [ count ]{ROW|ROWS}ONLY][ {FOR { UPDATE | SHARE...
Because of the GROUP BY clause, only one row containing the sum of all sales is returned for each sales order. G. Use GROUP BY with multiple groups The following example finds the average price and the sum of year-to-date sales, grouped by product ID and special offer ID. SQL Copy ...