SELECT DISTINCT agent_code, ord_amount, cust_code: This line specifies that you want to retrieve unique combinations of 'agent_code', 'ord_amount', and 'cust_code'. The DISTINCT keyword ensures that only unique combinations are returned; any duplicate combinations will be eliminated. FROM order...
ALL和DISTINCT选项指定是否应返回重复的行。如果没有给出这些选项,则默认值为ALL(返回所有匹配的行)。DISTINCT指定从结果集中删除重复的行。-- ALL DISTINCT -- 返回所有匹配的行 select state from t_usa_covid19_p; -- 相当于 select all state from t_usa_covid19_p; -- 返回所有匹配的行 去除重复的...
This SQL tutorial explains how to use the SQL DISTINCT clause with syntax and examples. The SQL DISTINCT clause is used to remove duplicates from the result set of a SELECT statement.
1、order by 会对输入做全局排序,因此只有一个reducer,会导致当输入规模较大时,需要较长的计算时间。 2、sort by不是全局排序,其在数据进入reducer前完成排序。因此,如果用sort by进行排序,并且设置mapred.reduce.tasks>1,则sort by只保证每个reducer的输出有序,不保证全局有序。 3、distribute by(字段)根据指定...
Sorts on a table with a Columnstore index are now in batch mode Windowing aggregates now operate in batch mode such asLAGorLEAD Queries on Columnstore tables with Multiple distinct clauses operate in Batch mode Queries running under MAXDOP 1 or with a serial plan execut...
Examples of SQL SELECT DISTINCT Multiple Columns Different examples are mentioned below: We are using distinct_multiple tables to define examples. Code: Select * from distinct_multiple; Output: Example #1 In the below example, we retrieve the count of unique records from multiple columns by using...
(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_...
Sorts on a table with a Columnstore index are now in batch mode Windowing aggregates now operate in batch mode such as LAG or LEAD Queries on Columnstore tables with Multiple distinct clauses operate in Batch mode Queries running under MAXDOP 1 or with a serial plan execute in Batch Mod...
SQL Comments SQL Data Types SQL Operators SQL Date and Time SQL JOIN Three Tables SQL SUBSTRING() SQL Commands SQL REPLACE() SQL REGEXP SQL Stored Procedures SQL Injection SQL Tutorials SQL SUM With GROUP BY SQL HAVING Clause SQL COUNT() With DISTINCT SQL RIGHT JOIN SQL COUNT() SQL...
hive模糊搜索表:show tables like '*name*'; 查看表结构信息:desc table_name; 查看分区信息:show partitions table_name; 加载本地文件:load data local inpath '/xxx/test.txt' overwrite into table dm.table_name; 从查询语句给table插入数据:insert overwrite table table_name partition(dt) select * from...