![]() In summary, A user-defined variable in MySQL is a variable that is defined and used by the user in SQL statements. It’s important to note that user-defined variables are different from system variables, which are defined and used by the MySQL server to configure its behavior. Once a user-defined variable is defined, it can be used in subsequent SQL statements, such as in a SELECT statement to retrieve data from a table: SELECT * FROM mytable WHERE id = can also use variables as part of expressions, for example, to increment or decrement a variable’s value: SET = + 1 INSERT INTO mytable (id, name) VALUES 'John') Assign value to it in an INSERT, UPDATE or DELETE statement.Assigning a value to it in a SELECT statement:.It means that once the connection to the MySQL server is closed, the value of the variable is lost.Ī user-defined variable can be defined in several ways: The value of a user-defined variable persists only for the duration of the current session. It is defined by using the symbol followed by the variable name. ![]() MySQL User-Defined VariableĪ user-defined variable in MySQL is a variable that is defined and used by the user in SQL statements. MySQL also supports the use of user-defined variables which persist only for the duration of the current session, and you can use variables as part of expressions, for example, to increment or decrement a variable’s value. Variables are defined using the symbol followed by the variable name, and once defined, they can be used in subsequent SQL statements. In summary, MySQL supports the use of variables, which can be used to store and manipulate data within SQL statements.
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