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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 -
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 -
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