In the front is a summary of common date functions, followed by a continuous date sql problem and its solution routine.
1. Current date and time
-- 2020-12-05 19:16:29.284
2. Get the current date, which is 2020-12-05
3. Obtain the timestamp under unix ...
Posted by jk11uk on Tue, 03 May 2022 06:12:50 +0300
Variety shows are not only a way to relax after a hard day, but also our talk after dinner. Looking at their favorite variety shows, time is beautiful enough. And "exciting offer" is a good variety choice. Some people say it makes me feel inferior, and I think it's very interesting.
"Exciting offer" has been broadcast for t ...
Posted by dustbuster on Tue, 03 May 2022 03:38:30 +0300
According to the source code of WordCount MapReduce program, we can draw the following conclusions: (1) The program has a main method to start the operation of the task, in which the job object stores the necessary information for the operation of the program, such as specifying Mapper class and Reducer class
Posted by php_newB on Mon, 02 May 2022 12:43:15 +0300
4.1 data integrity
The common method to detect damaged data is to calculate the checksum of the data when entering the system for the first time. If the newly generated checksum after transmission does not completely match the original checksum, the data will be considered damaged.
Note that the checksum may be wrong and the data is correct, ...
Posted by flash99 on Mon, 02 May 2022 12:03:14 +0300
Window functions are a special set of functions
Scan multiple input lines to calculate each output value, and generate a row structure for each row of data
Complex calculation and aggregation can be realized through window functions
By function, it can be divided into: sequence (sorting), aggregation and analys ...
Posted by fishdish on Mon, 02 May 2022 05:28:04 +0300
Vision: "make programming no longer difficult to learn and make technology and life more interesting"
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Episode 1 design mode of adding wings to the tiger - Introduction to decorator design mode
Episode 2 meet Lao Wang's refitting collocation - play with the desig ...
Posted by Russia on Sun, 01 May 2022 23:20:46 +0300
Loop is a method used by R to repeatedly complete a task. Let's use the score function to solve a practical problem.
The slot machine program simulates a group of controversial slot machines in real life, which are believed to be suspected of cheating. The return rate of these slot machines seems to be 40 cents / dollar, but the manuf ...
Posted by nikky_d16 on Sun, 01 May 2022 13:42:31 +0300
In the previous article, the pseudo-distribution deployment of Hadoop clusters was introduced. Before reading this, it is recommended to read the previous article: Hadoop cluster deployment (1)
In this article we will introduce the distributed deployment of Hadoop clusters.
Deployment of Distributed Clusters
Virtual machine preparation
Posted by jigaruu on Sun, 01 May 2022 08:36:38 +0300
Remark: Hive version 2.1.1
1. Overview of Hive SELECT (Data Query Language)
The select statement is the most frequently used statement in Hive, and it is also the statement with the most complex syntax. Many syntaxes of select statements are similar to traditional relational databases, which also facilitates the transition from tradition ...
Posted by sarika on Sat, 30 Apr 2022 08:55:28 +0300