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1 operator 1.1 arithmetic operators meaningoperatoraddition+subtraction-multiplication*division/ 1.2 comparison operators operatormeaning=Equal to<>And ~ are not equal>=Greater than or equal to>greater than<=Less than or equal to<less than 2 exercise part 1 - query 2.1 writing the product table The SQL code is as foll ...

1. sql Title Brushing There are two main purposes to do this topic, preparing for the interview and understanding the business logic and thinking style of the data analyst in practice. Most of the data analysts are biased toward the business side, with the indicators increasing or decreasing, how to analyze, from which angles to analyze, c ...

Build table 1. Table building syntax Table creation belongs to DDL statements, including create, drop and alter create table Table name (field name 1 data type, field name 2 data type, field name 3 data type,) 2. Data type varchar: variable length string, which is slow and saves space char: fixed length string. Regardless of the actual d ...

Single line function Single line function: Operation data object Accept parameters and return a result Transform only one row One result per row Data types can be converted Can be nested The parameter can be a column or a value function_name [(arg1, arg2,...)] Single-Row Functions Character function LOWER('SQL Course')--sql course UPPER ...

Practical application of canal Understand the principle of canal Canal is a middleware based on database incremental log parsing developed in java, which provides incremental data subscription and consumption. At present, canal mainly supports MySQL binlog parsing. After parsing, canal client is used to process the obtained relevant data. (da ...

The previous article introduced the configuration of F5 virtual machine environment. Refer to“ F5 load balancing configuration of database Series ”, here we continue to introduce MySQL configuration F5 load balancing. 2. F5 configure load balancing The F5 virtual machine is configured with three network cards. The information is a ...

catalogue 1, Advantages 2, Create databases and tables 3, Basic usage syntax (addition, deletion, modification and query)   1. Increase 2. Delete 3. Change 4. Check 1, Advantages Simple: compared with other large databases, MySQL is a relatively simple database system, which is easier to use than XiaobaiEconomy: compared with s ...

SSM mybatis usage process Official teaching Mybatis usage process 1. Import the coordinates of jar or mvan <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>provided</scope> </dependency> <dependency> <groupId&gt ...

JDBC 1. Functions of JDBC module: Responsible for database resource management and error management, which simplifies the operation of developers on the database. 2,JdbcTemplate: The Spring framework provides this class, which is the basis of the data abstraction layer of the Spring framework and the core class of Spring JDBC. 3. The JDBC ...

❣💞❣ Database foundation ② 1, 92 syntax join table query 1. Cross connect: corss join -- Cross connect select * from emp cross join dept; 2. natural join Note: if there are multiple fields with the same name, they will be connected equally -- Inner connection select * from emp natural join dept; 3. Using connection: Join using ( ...