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- The database is divided into databases and tables. When? How to divide?
- The relational database itself is more likely to become a system bottleneck, as the storage capacity, number of connections, and processing capabilities of a single machine are limited. When the data volume of a single table reaches 1000W or 100G, due to the large number of query dimensions, even if slave databases are added and indexes are optimized, performance will still drop severely when performing many operations. At this time, it is necessary to consider segmenting it. The purpose of segmentation is to reduce the burden on the database and shorten the query time.
- SQL 1046 2023-08-17 16:31:55
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- Interview question: How to optimize MySQL in daily work?
- Common MySQL optimization methods are divided into the following aspects: SQL optimization, design optimization, hardware optimization, etc., each of which includes multiple small optimization points.
- SQL 1111 2023-08-17 16:26:10
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- sql in operator usage
- SQL in operator usage: 1. Single column matching, you can use the IN operator to match multiple values in a column; 2. Multi-column matching, the IN operator can also be used to match values in multiple columns; 3. Subquery, The IN operator can also be used with a subquery, which is a query statement nested within the main query.
- SQL 4101 2023-08-04 15:58:07
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- Why do code specifications require SQL statements not to have too many joins?
- When I was in school, my database teacher liked to take the database paradigm test the most. It wasn’t until I went to work that I learned that everything should be based on performance. Redundant if it can be redundant, and join if it cannot be redundant. If join really affects performance. Try increasing your join_buffer_size, or change to a solid state drive.
- SQL 1171 2023-07-26 16:51:04
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- sql case when usage
- The usage of sql case when allows different operations to be performed based on different conditions. Whether it's a simple classification or complex nested conditions, the CASE WHEN statement provides a flexible and readable way to handle different situations. By mastering and using the CASE WHEN statement proficiently, we can better process and analyze data.
- SQL 2180 2023-07-17 15:42:44
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- case when usage in sql
- Case when in SQL is used to perform different operations based on different conditions in SQL queries. You can make judgments based on any conditions and perform corresponding operations based on the results of the conditions. The working principle of the CASE WHEN statement is to judge the conditions one by one from top to bottom. Once a condition is met, the corresponding operation will be performed, and only the first one that satisfies the condition will be executed. Conditional operations.
- SQL 6757 2023-07-17 15:37:36
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- Insert into select statement
- The Insert into select statement is a SQL statement used to insert query results into the target table. It allows us to insert data from one table into another table while also performing any required transformations or filtering on the data. This syntactic structure is very useful when dealing with transformations and integrations between data sets.
- SQL 5013 2023-07-06 16:50:16
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- Usage of insert into select
- INSERT INTO SELECT is a common SQL statement used to insert the results of one query into another table. This syntax structure is very useful to easily copy data from one table to another table, or to filter and insert data based on some conditions.
- SQL 34179 2023-07-06 16:47:15
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- What is sql insert statement
- The sql insert statement is "INSERT INTO", which is used to insert new data rows into the table. There are two basic syntaxes: "INSERT INTO table name (field name 1, field name 2,... field name N) VALUES (value 1 , value 2,... value N);" and "INSERT INTO table name VALUES (value 1, value 2,... value N);"; if the field name is omitted, ensure that the order of the inserted values is consistent with that in the table The fields are in the same order.
- SQL 36719 2023-02-01 16:18:51
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- 因为一条sql语句产生了自我怀疑！
- 本篇文章给大家带来了关于sql的相关知识，其中主要介绍了作者在开发过程中遇到的sql问题，下面一起来看看博主是怎么解决的吧，也希望本文的方法对大家有帮助。
- SQL 2014 2022-12-30 16:35:32
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- What are the characteristics of nosql database
- Features of nosql: 1. Flexible scalability; nosql removes the relational characteristics of relational databases, there is no relationship between data, and it can be easily expanded. 2. Flexible data model; NoSQL uses non-relational models such as key/value and column family, allowing different types of data to be stored in one data element. 3. NoSQL can rely on its good horizontal expansion capabilities to make full use of cloud computing infrastructure and integrate well into the cloud computing environment. 4. Nosql has very high reading and writing performance, especially when dealing with large amounts of data. 5. High availability.
- SQL 21068 2022-11-28 19:44:10
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- Organize and summarize basic SQL statements based on examples
- This article brings you relevant knowledge about SQL. It mainly introduces the organization of basic SQL statements, including DDL, DML, DQL, etc. Let's take a look at it together. I hope it will be helpful to you.
- SQL 2690 2022-11-16 20:50:21
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- Examples of conversion operations between dates and strings in SQL
- This article brings you relevant knowledge about SQL, which mainly introduces the relevant content of converting dates and strings. Let's take a look at it together. I hope it will be helpful to everyone.
- SQL 6248 2022-11-03 20:39:40
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- SQL Server graphic method for operating database across servers (LinkedServer)
- This article brings you relevant knowledge about SQL, which mainly introduces the graphic method of SQL Server cross-server database operation. SQL Server Management Studio (SSMS) is an integrated environment for managing SQL Server infrastructure. The following is Let's take a look, hope it helps everyone.
- SQL 2560 2022-11-02 16:13:14
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- SQL Server restore full backup and differential backup operation process
- This article brings you relevant knowledge about SQL Server. It mainly introduces the detailed operations of SQL Server restore full backup and differential backup. This article introduces you to you in great detail through pictures and texts. Let’s take a look at it together. I hope Helpful to everyone.
- SQL 2441 2022-09-13 17:33:34
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