AVG_IF

AVG_IF

后缀 -If 可以附加到任何聚合函数的名称后。在这种情况下，聚合函数会接受一个额外的参数——条件。

AVG_IF(<column>, <cond>)

示例

创建表并插入示例数据

CREATE TABLE employees (
  id INT,
  salary INT,
  department VARCHAR
);

INSERT INTO employees (id, salary, department)
VALUES (1, 50000, 'HR'),
       (2, 60000, 'IT'),
       (3, 55000, 'HR'),
       (4, 70000, 'IT'),
       (5, 65000, 'IT');

查询示例：计算 IT 部门的平均薪资

SELECT AVG_IF(salary, department = 'IT') AS avg_salary_it
FROM employees;

结果

| avg_salary_it   |
|-----------------|
|     65000.0     |