用逗号连接后面过滤条件用 where ,用 join 连接后面过滤条件是 on。 order by 排序 全局排序,只会有一个reduceASC(ascend): 升序(默认)DESC(descend): 降序SELECT*FROMstudent sLEFTJOINscore scoONs.s_id=sco.s_idORDERBYsco.s_scoreDESC; 注意:order by 是全局排序,所以最后只有一个reduce,也就是在一个...
从查询语句给table插入数据:insert overwrite table table_name partition(dt) select * from table_name; 导出数据到本地系统:insert overwrite local directory '/tmp/text' select a.* from table_name a order by 1; 创建表时指定的一些属性: 字段分隔符:row format delimited fields terminated by '\t' ...
Multiple Lateral View可以实现类似笛卡尔乘积。Outer关键字可以把不输出的UDTF的空结果,输出成NULL,防止丢失数据。 行转列 相关参数说明: CONCAT(string A/col, string B/col…):返回输入字符串连接后的结果,支持任意个输入字符串; CONCAT_WS(separator, str1, str2,...):它是一个特殊形式的 CONCAT()。第一...
.groupBy({favoriteColor:"asc", eyeColor:"desc"}) // Multiple group bys aren't a problem! .having(["users" ,">", 2]) // Having uses the same syntax as WHERE, but runs after the GROUP BY command. .orderBy({users:"desc"}) .exec().then(function(rows) {...}) // Look mah,...
How do I query row-by-row, and what if I need to look at multiple rows at once? (simple select, limit, distinct, order by, group by, where vs having) What complex expressions can I select? (null, is null, coalesce, case) Do I care about data types? (json, jsonb, date/times...
An innovation in SQL Server 7.0 is the hash team. In simple terms, many queries consist of multiple execution phases; where possible, the query optimizer should take advantage of similar operations across multiple phases. For example, you want to know how many order line items have been entered...
It’s usually listed as one of the last rows in a query, after any joins or where statements; typically you’ll only seeHAVING,ORDER BY, orLIMITstatements following it in a query You can group by multiple fields (ex.group by 1,2,3) if you need to; in general, we recommend performi...
ORDER BY ID; II)SQLPLUS中的SET TRACE即可看到Execution Plan Statistics SET AUTOTRACE ON; 3. 如何使用CBO,CBO与RULE的区别 IF初始化参数 OPTIMIZER_MODE = CHOOSE THEN --(8I DEFAULT) IF做过表分析 THEN优化器 Optimizer=CBO(COST); /*高效*/ ...
SELECTSTRFTIME('%Y/%m',ORDER_DATE),REVENUE Multiple aggregations in one query The simple SQL query generator idea looks interesting. But we can take it even further. What if we need to compute theREVENUEfor two different product categories (e.g. 'Home', and 'Outdoor') and aggregate it by...
sql-rank()，具有多个where和group by使用一个cte，它将为每个cte返回不同的行user_id以及date_...