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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 -
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 -
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 -
Hacken Lee's new album "Fairy Tales of Adults" goes online to Huawei Music
On May 12, it was reported that Hacken Lee's Cantonese album "Adult's Fairy Tales", the "King of Love Songs", was launched on Huawei Music, with a total of 9 songs.The "Fairy Tales of Adults" includes new Cantonese songs such as "Xian Xu", "Green's Fairy Tales", and "Hungry Caterpillar"...
internet 2023-05-12 10:21:21
