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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 -
Steps to connect to a SQL Server database through Linux installation of ODBC
catalogue1. Download the ODBC installation package2...
Database Operation Tutorial 2023-05-12 12:13:06 -
SQL Server 2022 AlwaysOn New Features including Availability Group Details
catalogueHow to create an availability group?How to use including availability groups?3. Metadata synchronization verification3...
Database Operation Tutorial 2023-05-12 12:12:54 -
SQLServer Index Fragmentation Query and Processing of Tables
1.2...
Database Operation Tutorial 2023-05-12 12:12:48 -
Using SQL; Server partition table function improves database read/write performance
Generally speaking, the first bottleneck point in a system is likely to be the database. For example, our production system has a high concurrency...
Database Operation Tutorial 2023-05-12 12:12:34 -
Introduction to SQL Injection with SQL Map
catalogue1 Determine if there is an injection point2 Query all databases under the current user3 Obtain the table names in the database4 Get the field names in the table5 Get Field Content6 Obtain all users of the database7 Obtain the password of the database user8 Obtain the name of the current website database9 Obtain the user name of the current website databaseOriginally, SQL injection was so simpleTaking the first level of SQL injection into the shooting range sqli labs as an example, share the use of sqlmap tools.1 Determine if there is an injection pointUsing commands:Using commands:sqlmap-u" http://49...
Database Operation Tutorial 2023-05-12 12:12:30 -
Mastering SQL Server Practical Tutorial - SQL Server Installation Guide
cataloguepreface1 Introduction to Database1.1 Classification of databases1...
Database Operation Tutorial 2023-05-12 12:12:14 -
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 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
