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This topic is similar to some of the search topics in Leetcode. The problem you want to deal with is: count the number of two adjacent digits of a word. If there are w1,w2,w3,w4,w5,w6, then: The final output is (word,neighbor,frequency). We implement it in five ways: MapReduce Spark Spark SQL method Scala method Spark SQL for Scala MapReduce ...

1, Read data source (1) Read json and use spark.read. Note: the path is from HDFS by default. If you want to read the native file, you need to prefix it file: / /, as follows scala> val people = spark.read.format("json").load("file:///opt/software/data/people.json") people: org.apache.spark.sql.DataFrame = [age: bigint, name: string] scal ...

In the process of configuration, initiation and recovery of Oracle database backup, many Oracle database commands are needed. In this chapter, I will sort out the commands for your reference. Oracle user and instance related commands Linux/Unix platform # ps -ef | grep [p]mon orauxdb 18751 1 ...

(1) Database creation 1) Database classification System database and user database; distinguish database type by viewing object Explorer; Note: the master database should not be moved. This is the database of the database. We mainly study the user database; 2) User database file composition T ...

/****** ******/ //Initialization data create table employee (empid int, deptid int, salary decimal(10, 2)) insert into employee values(1, 10, 5500.00) insert into employee values(2, 10, 4500.00) insert into employee values(3, 20, 1900.00) insert into employee values(4, 20, 4800.00) insert into employee values(5, 40, 6500.00) insert ...

Demand: stores under each platform classification, name, picture path and score of each store, name, picture path and score of four products under each store Train of thought: At the beginning, stores are dynamic and easy to write, just use Ajax. But it's a bit unrealistic to ask for a query for the products under each store. At the beginning, ...

Preface Before learning to operate MYSQL database with JAVA program, we need to download and configure it Eclipse and jdk1.8 , and the tools most needed this time: MySQL database and JDBC driver Download driver jdbc 8.0.11 download website: https://dev.mysql.com/downloads/connector/j/ Load driver Open eclipse and righ ...

Stored procedure A set of SQL statements used to complete specific database functions, which are compiled and stored in the database system. In use, the user calls and executes the stored procedure by specifying the defined stored procedure name and giving the corresponding stored procedure parameters, thus completing one or a series of databas ...

Reproduced from: https://blog.csdn.net/caoxiaohong1005/article/details/72571798 1. select into outfield function: Export data to the specified directory of pc. 2. Syntax: SELECT ... INTO OUTFILE 'file_name' [CHARACTER SET charset_name] [export_options] export_options: [{FIELDS | COLUMNS} [T ...

Reproduced from: https://blog.csdn.net/caoxiaohong1005/article/details/72571798 1. select into outfield function: Export data to the specified directory of pc. 2. Syntax: SELECT ... INTO OUTFILE 'file_name' [CHARACTER SET charset_name] [export_options] export_options: [{FIELDS | COLUMNS} [T ...