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1, GROUPING SETS Grouping sets allows the user to specify multiple column lists to group. Sets the column of the given word list that does not belong to the grouping column to NULL For example, the demand makes statistics on order sales by store grouping, order group grouping, store and order group grouping respectively, and obtains the result ...

Why have multiple watches? – create an employee table, including the following (id, name, age, dep_name, dep_location),id primary key, automatic growth, and add 5 pieces of data Code example: CREATE TABLE emp ( id INT PRIMARY KEY auto_increment, name VARCHAR(40), age int, dep_name VARCHAR(40), dep_location VARCHAR(30) ); INSERT INTO em ...

Suddenly a question came to mind: every time we execute SQL Will create one SqlSession，Then in a transaction, multiple mapper Execute multiple sql，each sql Will be created sqlSession Are you? Run a Demo test Test whether a SqlSession will be created for each request when no transaction is added to the method: It can be seen from the log t ...

catalogue1, Column query2, Query all columns in the table3, Set alias for column4, Constant query5, Remove duplicate rows from results6, Select records according to the WHERE statement7, Writing method of notessee also Learning focus Use the SELECT statement to SELECT data from a table. Set an alias for the column to display. Constants o ...

catalogue0. Date and time type0.0 time type1. Conversion function1.1 CAST1.2 CONVERT2. Date operation function2.0 GETDATE and getutdate2.1 SYSDATETIME and SYSUTCDATETIME2.2 DATEADD2.3 DATEDIFF2.4 DATEPART and DATENAME2.5 YEAR, MONTH and DAY2.6 ISDATE3. Comprehensive use example3.1 age based on date of birth3.2 to be supplemented Zhiming - Octob ...

preface It's really a time of trouble recently. For the first time, classes that usually don't leave homework have left homework recently. Recently, the rhythm of doing questions has been disrupted. Alas, I'm speechless. Later, I want to write an article about flash. I don't know when I will have a chance. Now I'd better focus on sql injection ...

Table management functions: help define tables with geometry fields AddGeometryColumn Add a field of geometry type to an existing table Function type: text AddGeometryColumn(varchar table_name, varchar column_name, integer srid, varchar type, integer dimension, boolean use_typmod=true); AddGeometryColumn(varchar schema_name, varchar ta ...

0x00 introduction Why do we study the first chapter? Because friends who read this article have probably read the file upload series I wrote earlier. If we come to SQL injection here, we can easily understand it. At the same time, SQL injection is also what we often want to find in audit. Since comparison, it is unrealistic to get shell, and t ...

Motianlun online training platform V1.0 is released. It provides a deployed database online environment for free. You can open the browser for learning anytime and anywhere and connect to the Linux WEB terminal with one click. At present, it supports Oracle, MySQL, Redis, PostgreSQL, openGauss and MogDB. Adhering to the vision of knowing and e ...

5 others 5.3 stored procedures and functions Similar to C + + functions 5.3.1 stored procedure Meaning: a set of SQL statements with pre compiled numbers (batch statements) Benefits: Improve code reusabilitySimplify operationThe compilation times are reduced, the connection times with the database server are reduced, and the efficiency is ...