mysql中如何查询赋值给变量

-- 使用SET语句
SET @myVariable = (SELECT column_name FROM table_name WHERE condition);

-- 或者使用SELECT语句
SELECT column_name INTO @myVariable FROM table_name WHERE condition;

SELECT @myVariable := column_name FROM table_name WHERE condition;

SET @myVariable = 'some_value';
SELECT * FROM table_name WHERE column_name = @myVariable;

CREATE TABLE employees (
    id INT PRIMARY KEY,
    name VARCHAR(100),
    salary DECIMAL(10, 2)
);

INSERT INTO employees (id, name, salary) VALUES
(1, 'Alice', 50000),
(2, 'Bob', 60000),
(3, 'Charlie', 70000);

SET @highestSalary = (SELECT MAX(salary) FROM employees);
SELECT @highestSalary;