20、 select(cols:string*) dataframe 做字段的刷选 df.select($“colA”, $“colB” + 1) 21、 selectExpr(exprs: String*) 做字段的刷选 df.selectExpr(“name”,“name as names”,“upper(name)”,“age+1”).show(); 22、 sort(sortExprs: Column*) 排序 df.sort(df(“age”).desc).show(...
20. select(cols:string*) dataframe 做字段的刷选 df.select($“colA”, $“colB” + 1) 21. selectExpr(exprs: String*) 做字段的刷选 df.selectExpr(“name”,“name as names”,“upper(name)”,“age+1”).show(); 22. sort(sortExprs: Column*) 排序 df.sort(df(“age”).desc).show();...
CREATE VIEW user1 AS SELECT id, salary FROM default.employee WHERE name = 'user1'; CREATE VIEW user2 AS SELECT id, salary FROM default.employee WHERE name = 'user2'; USE default; CREATE GLOBAL TEMP VIEW temp1 AS SELECT 1 AS col1; CREATE TEMP VIEW temp2 AS SELECT 1 AS col1; 1. ...
Selecting rows(行), columns(列) 代码语言:javascript 代码运行次数:0 复制Cloud Studio 代码运行 # Create the SparkDataFrame df <- as.DataFrame(faithful) # 获取关于 SparkDataFrame 基础信息 df ## SparkDataFrame[eruptions:double, waiting:double] # Select only the "eruptions" column head(select(df,...
SelectExpressionItem selectExpressionItem =null; AllTableColumns allTableColumns =null; Alias alias =null; SimpleNode node =null;if(selectItemlist !=null) {for(inti =0; i < selectItemlist.size(); i++) { selectItem = selectItemlist.get(i);if(selectItem instanceof SelectExpressionItem) {...
3、Select union 查询 select * from test union all select * from test0;(合一) select * from test union select * from test0;(去重) select * from (select * from test union select * from test0) a; select a from (select * from test union all select * from test0) a; ...
二、Columns列操作 2.1 引用列 Spark 支持多种方法来构造和引用列,最简单的是使用col()或column()函数。 col("colName")column("colName")// 对于 Scala 语言而言,还可以使用$"myColumn"和'myColumn 这两种语法糖进行引用。df.select($"ename",$"job").show()df.select('ename, 'job).show() ...
sum(Column): Returns the sum of all values in the specified column. You can use the following statement inSpark SQLto obtain each shipper's freight sum, as shown in the following figure. selectShipper,sum(Freight) fromDB Table Input-3 ...
MyTable[#All]: Table of data. Reading will return all rows and columns in this table. Writing will only write within the current range of the table. No growing of the table will be performed. PRs to change this are welcome.更多详细可以参考:https://github.com/crealytics/spark-excel/作者...
spark-sql> ANALYZE TABLE customer COMPUTE STATISTICS FOR COLUMNS c_customer_sk, c_customer_id, c_current_cdemo_sk; Time taken: 9.139 seconds spark-sql> desc extended customer c_customer_sk; col_name c_customer_sk data_type bigint