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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 -
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 -
Sql Server Management Implementation steps for Studio to connect to MySQL
targetGiven MySQL connection parameters (address and user), expect to use Microsoft; SqlServer Management Studio (hereinafter referred to as MSSSMS) connects to MySQL and directly queries or modifies data in MySQL in MSSSMS.realizationStep 1/4: Download and install MySqlConnector/ODBC at MySQL:: DownloadConnector/ODBCSelect the corresponding installation file based on the number of bits in the operating system...
Database Operation Tutorial 2023-05-12 12:13:01 -
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 -
SQL Server 2012 High Availability Solution
SQL Server 20one2 provides multiple solutions for high availability, such as:one. By using alwayson, virtual IP addresses (VIPs) can be provided to achieve failover and read scalability...
Database Operation Tutorial 2023-05-12 12:12:46 -
SQL Server 2012 Building Database AlwaysOn (Database High Availability Cluster)
To achieve a highly available database cluster, the following aspects need to be considered:1. Database selectionSelect a database that supports high availability...
Database Operation Tutorial 2023-05-12 12:12:42 -
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 -
Detailed explanation of SQL Server's memory management architecture
WindowsSQL Server 2.12...
Database Operation Tutorial 2023-05-12 12:11:27 -
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 -
SQL Server's execution plan
catalogue1 Background2 Display and Save Execution Plan3 Display estimated execution plan4 Display actual execution plan5 Save execution plan in XML format6 Compare and analyze execution plans6.1 Comparison of execution plans6...
Database Operation Tutorial 2023-05-12 12:11:18 -
SQL Detailed explanation of sub queries for Server
catalogue1 Basic knowledge of sub queries2 Sub query rules3 Column names in qualified subqueries4 Multi layer nesting of subqueries5 Related sub queries6 Sub query typesummary1 Basic knowledge of sub queriesA subquery is a query nested within a SELECT, Insert, UPDATE, DELETE statement, or another subquery.You can use subqueries anywhere an expression is allowed...
Database Operation Tutorial 2023-05-12 12:11:06 -
SQL Server Single Table Data Query Example Explanation
catalogue1 Import data into SQL Server2 Example questions1. Query all information of all students2...
Database Operation Tutorial 2023-05-12 12:11:01