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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 -
Complete uninstallation and reinstallation of SQL Server
catalogueComplete uninstallation and reinstallation of SQL Server1. Control Panel Delete Names with&quo; SQL” Procedure for2...
Database Operation Tutorial 2023-05-12 12:13:17 -
SQLServer Index Fragmentation Query and Processing of Tables
1.2...
Database Operation Tutorial 2023-05-12 12:12:48 -
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 -
VS comes with SQL; Server changes password and connects for use
Next, please follow these steps:After completing the above steps, you should be able to usesaConnect the user and their password to the SQLServerExpressLocalDB instance in the program. Simply use" in the connection string; UserId=sa" And" Password=YourPassword" (Among themYourPasswordIt is the actual password you set...
Database Operation Tutorial 2023-05-12 12:12:09 -
SQL Server database judgment of the latest backup execution results (latest recommended)
1 2 errorlogtrace3 backupset4 SQL1 SQL Servermsdb.dbo...
Database Operation Tutorial 2023-05-12 12:12:02 -
SQL Server judges whether there is summary for database, table, column, view, stored procedure and function
catalogue1 Introduction Overview2 Database related judgments2.1...
Database Operation Tutorial 2023-05-12 12:11:57 -
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 -
SQLserver2019 Express Installation and Some Problem Solving
Firstly, I am a technical novice who does not have a thorough understanding of some theoretical issues. If everyone has any problems, we can discuss them together and grow each other...
Database Operation Tutorial 2023-05-12 12:11:46 -
SQL Server 2022 Installation Tutorial (latest recommended)
catalogue1 Configuring and installing SQL Server(1) Download link on official website2 Install visualization tool SSMS3 Common installation errorsSQL Server is a relational typeDatabase Management System(RDBMS), composed ofMicrosoftCompany development and maintenance. It supports Structured Query Language (SQL) and Transact SQL (T-SQL), and is a scalable database platform used to process large amounts of data and support high-performance data access, with a wide range of applications...
Database Operation Tutorial 2023-05-12 12:11:34 -
Practical cases of SQL Server database connection queries and sub queries
cataloguepreface1. Query the student ID, name, elective course ID, and grades of all students2...
Database Operation Tutorial 2023-05-12 12:11:09
