Rules of precedence for operators in an expression Sorting rows using the ORDER BY clause Substitution variables DEFINE and VERIFY commands 1、Restrict 限制(Where-condition)The essential capabilities of SELECT statement are Selection, Projection and Joining. Displaying specific columns from a table is ...
# Query_time: 91.511261 Lock_time: 0.000124 Rows_sent: 2050008 Rows_examined: 2150010 Thread_id: 19187 Errno: 0 Killed: 0 Bytes_received: 0 Bytes_sent: 58061725 Read_first: 2 Read_last: 0 Read_key: 2 Read_next: 0 Read_prev: 0 Read_rnd: 0 Read_rnd_next: 2150012 Sort_merge_passes...
ORDER BY 子句 管線操作員 PIVOT 子句 查詢 取樣查詢 SELECT 設定作業 SORT BY 子句 SQL 資料流操作 星星條款 資料表值函數 表格參考 UNPIVOT 子句 WATERMARK 子句 WHERE 子句 WINDOW 條款 WINDOW 框架條款 ANALYZE TABLE CACHE TABLE CLEAR CACHE REFRESH FUNCTION REFRESH TABLE REFRESH UNCACHE TABLE DESCRIBE CATALO...
[l_orderkey])) |--Sort(ORDER BY:([ORDERS].[o_orderkey] ASC)) | |--Parallelism(Repartition Streams, PARTITION COLUMNS: ([ORDERS].[o_orderkey])) | |--Index Seek(OBJECT: ([tpcd1G].[dbo].[ORDERS].[O_DATKEYOPR_IDX]), SEEK:([ORDERS].[o_orderdate] >= Apr 1 2000 12:00AM...
order by 排序:ASC(ascend): 升序(默认) DESC(descend): 降序 sort by 局部排序:每个MapReduce内部进行排序,对全局结果集来说不是排序。 distribute by 分区排序:类似MR中partition,进行分区,结合sort by使用 Hive函数 1. 聚合函数 指定列值的数目:count() ...
Distinct count with multiple columns distinct vs group by performance wise Divide time into Morning , After noon , Evening and Night Do I need to INCLUDE the primary key in an index or not? Do not select the last row Does anyone know how to find a period character in a string? Does ca...
(orALTERTABLERECOVERPARTITIONS)--显示数据库/SCHEMAS,表,表属性,视图,分区,函数,索引,列,建表语句SHOWDATABASES/SCHEMAS,TABLES,TBLPROPERTIES,VIEWS,PARTITIONS,FUNCTIONS,INDEX[ES],COLUMNS,CREATETABLE--显示详细信息,数据库/SCHEMA,表,视图,物化视图DESCRIBEDATABASE/SCHEMA,table_name,view_name,materialized_view_...
3.Can we use DISTINCT with an ORDER BY clause? Yes, we can use DISTINCT with an ORDER BY clause to sort the distinct results based on one or more columns. 4.How does the COUNT() function interact with DISTINCT on multiple columns?
在后向兼容语法中,WITH SORT_IN_TEMPDB 等同于 WITH SORT_IN_TEMPDB = ON。 IGNORE_DUP_KEY = { ON | OFF } 指定在插入操作尝试向唯一索引插入重复键值时的错误响应。 IGNORE_DUP_KEY 选项仅适用于创建或重新生成索引后发生的插入操作。 当执行 CREATE INDEX、ALTER INDEX 或UPDATE 时,该选项无效。 默认值...
SQL 中 Group By 语句大家都很熟悉,根据指定的规则对数据进行分组,常常和聚合函数一起使用。 比如,考虑有表 dealer,表中数据如下: 如果执行 SQL 语句 SELECT id, sum(quantity) FROM dealer GROUP BY id ORDER BY id,会得到如下结果: +---+---+ | id|sum(quantity...