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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 -
Summary of three methods for creating SQL Server databases
catalogue1 Creating a database using SQL Server Management Studio2 Create a database using the CREATE DATABASE statement.3 Creating a database using a templatesummaryThere are three ways to create a database...
Database Operation Tutorial 2023-05-12 12:13:22 -
Solution to Short Term Forced Expiration of SQL Server Database Passwords
1. Open Sqlserver, select the account under the login name, right-click, and click Properties2...
Database Operation Tutorial 2023-05-12 12:13:01 -
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 -
Summary of 5 Methods for Creating Indexes in SQL Server
cataloguePreliminary preparation:Create clustered indexMethod 1Method 2Create composite indexCreate overlay indexCreate Unique IndexFilter IndexSummary:Preliminary preparation:createtableEmployee(IDintnotnullprimarykey,Namenvarchar(4),Credit_ Card_ IDvarbinary(max));--- Be careful with this data type. goExplanation: All indexes on this table will be deleted before creating the next index...
Database Operation Tutorial 2023-05-12 12:11:54 -
Hacken Lee's new album "Fairy Tales of Adults" goes online to Huawei Music
On May 12, it was reported that Hacken Lee's Cantonese album "Adult's Fairy Tales", the "King of Love Songs", was launched on Huawei Music, with a total of 9 songs.The "Fairy Tales of Adults" includes new Cantonese songs such as "Xian Xu", "Green's Fairy Tales", and "Hungry Caterpillar"...
internet 2023-05-12 10:21:21
