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Summary of several methods for removing duplicate data in SQL (window function for data deduplication)
catalogueMethod 1: distinctMethod 2: groupbyMethod 3: Window functionWhen using SQL to extract and analyze data, we often encounter scenarios where data is duplicated, requiring us to perform data deduplication and subsequent analysis.Taking the sales report of a certain e-commerce company as an example, we commonly use distinct or group by statements to deduplicate data...
Database Operation Tutorial 2023-05-12 12:13:26 -
How to Convert Horizontal and Vertical Tables in SQL
catalogue1 Overview of Horizontal Tables2 Overview of the vertical table3 The code for converting a vertical table to a horizontal table is as follows and the view is displayed4 The code for converting horizontal table to vertical table is as follows and the view is displayed5 Advantages and disadvantages of horizontal and vertical tables6 Summary1 Overview of Horizontal TablesHorizontal table is a common way to create tables. For example, the table structure is primary key, field 1, field 2, and field 3…...
Database Operation Tutorial 2023-05-12 12:12:25 -
How to use Pycharm to connect to SQL Server (detailed tutorial)
SQL Sever1433 pycharmpycharmSQL SeverTipSQL Sever: ------------------------------ LAPTOP-40O6HVDS ------------------------------ : (provider: Shared Memory Provider, error: 0 - ) (Microsoft SQL Server: 233) SQL Sever SQL Sever Window create database soft2104soft2104soft2104pycharmuse master --drop database soft2104 -- yunmengzepycharmSQL Sever 123456123456pycharm db_ower SQL Sever SQL Sever: ------------------------------ LAPTOP-40O6HVDS ------------------------------ : (provider: Shared Memory Provider, error: 0 - ) (Microsoft SQL Server: 233) 1433 1433 1433winRcmdtelnet localhost 1433'telnet' winRcontrol Windows Telnet1winRcmdtelnet localhost 1433localhost....
Database Operation Tutorial 2023-05-12 12:12:22 -
Row_ Summary of the usage of the number() function
Row_ The number() function is a type of SQLSERVER system function that assigns a continuous integer to each row in the partition of the result set. Simply put, it is to generate a unique table with the sequence number starting from the first row of each partition...
Database Operation Tutorial 2023-05-12 12:12:05 -
SQL Detailed explanation of server's row level security
catalogue1 Preface2 Description3 Permissions4 Security note: Side channel attack5 Cross functional compatibility6 Example1 PrefaceRow level security allows you to control access to rows in database tables using group membership or execution context.Row level security (RLS) simplifies security design and coding in applications...
Database Operation Tutorial 2023-05-12 12:11:21 -
Ideal Car: The Glory and Hidden Worries of the 'New Power Brother'
The management team of Ideal Automobile stated that it aims to deliver 30000 units of sales in June, and the core goal for the second quarter is to increase the market share from 11% in the first quarter to 13%; The city NOA early bird test will be launched in June.Author | SilinEditor | YuchenIdeal Automobile's financial report for the first quarter of 2023 has been released...
Intelligent devices 2023-05-12 11:12:18 -
On Thursday, US stocks: The Dow fell four times in a row, Google rose more than 4%, and JD.com and Pinduoduoduo rose more than 7%
On May 12th, it was reported that on Thursday, US time, the main stock indexes of the US stock market closed with mixed gains and losses, with the Nasdaq slightly rising. Data shows a slowdown in the US job market, while the market is once again concerned about the health of banks in the US region...
internet 2023-05-12 07:46:00
