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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 -
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 The issue of not being able to fully utilize the number of logical cores in the CPU in 2016
Recently, I encountered a problem in my work where sqlserver2016 cannot fully utilize the CPU core. Through analysis tools, I can see that;There are a total of 72 CPU cores, but SQL Only 40 cores can be used, and many people have encountered this problem...
Database Operation Tutorial 2023-05-12 12:12:37 -
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 -
SQL Server Detailed steps for changing the default backup directory for databases
This article also applies to the latest version of SQL server 2008, 2016, 2019Open SSMSSelect Database, right-click, PropertiesSelect&quo; Permissions”, Click on&quo; View Server Permissions&# quo;Select&quo; Database Settings;, Modify&quo; Backup; Box PathNote: After changing the backup path of a database, it is valid for all databases. Please note that the final prompt indicates whether to save...
Database Operation Tutorial 2023-05-12 12:12:17 -
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 -
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 -
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
