MAX_IF
MAX_IF
The suffix _IF can be appended to the name of any aggregate function. In this case, the aggregate function accepts an extra argument – a condition.
MAX_IF(<column>, <cond>)
Example
Create a Table and Insert Sample Data
CREATE TABLE sales (
  id INT,
  salesperson_id INT,
  product_id INT,
  revenue FLOAT
);
INSERT INTO sales (id, salesperson_id, product_id, revenue)
VALUES (1, 1, 1, 1000),
       (2, 1, 2, 2000),
       (3, 1, 3, 3000),
       (4, 2, 1, 1500),
       (5, 2, 2, 2500);
Query Demo: Find Maximum Revenue for Salesperson with ID 1
SELECT MAX_IF(revenue, salesperson_id = 1) AS max_revenue_salesperson_1
FROM sales;
Result
| max_revenue_salesperson_1 |
|---------------------------|
|           3000            |