| category | region  | sales |
|----------|---------|-------|
| 電子產(chǎn)品 | 華北    | 1000  |
| 電子產(chǎn)品 | 華東    | 1500  |
| 家居用品 | 華北    | 800   |
| 家居用品 | 華南    | 1200  |

SELECT 
    IFNULL(category, 'All Categories') as category,
    IFNULL(region, 'All Regions') as region,
    SUM(sales) as total_sales
FROM sales_data
GROUP BY category, region WITH ROLLUP;

| category       | region      | total_sales |
|----------------|-------------|-------------|
| 電子產(chǎn)品      | 華北        | 1000        |
| 電子產(chǎn)品      | 華東        | 1500        |
| 電子產(chǎn)品      | All Regions | 2500        | ← 電子產(chǎn)品小計
| 家居用品      | 華北        | 800         |
| 家居用品      | 華南        | 1200        |
| 家居用品      | All Regions | 2000        | ← 家居用品小計
| All Categories | All Regions | 4500        | ← 總計行

SELECT 
    YEAR(order_date) as year,
    QUARTER(order_date) as quarter,
    MONTH(order_date) as month,
    SUM(amount) as revenue
FROM orders
GROUP BY YEAR(order_date), QUARTER(order_date), MONTH(order_date)
WITH ROLLUP;

SELECT 
    warehouse,
    product_type,
    COUNT(*) as item_count,
    SUM(quantity) as total_quantity
FROM inventory
GROUP BY warehouse, product_type WITH ROLLUP;

SELECT 
    category,
    region,
    SUM(sales) as total_sales,
    GROUPING(category) as is_category_summary,
    GROUPING(region) as is_region_summary
FROM sales_data
GROUP BY category, region WITH ROLLUP;

SELECT 
    IFNULL(category, 'Total') as category,
    SUM(CASE WHEN region='華北' THEN sales END) as north,
    SUM(CASE WHEN region='華東' THEN sales END) as east,
    SUM(sales) as subtotal
FROM sales_data
GROUP BY category WITH ROLLUP;

select
    COALESCE(driver_id, '總體') as driver_id,
    round(avg(grade), 1) as grade
from
    tb_get_car_order
where
    driver_id in (
        select
            driver_id
        from
            tb_get_car_record
            join tb_get_car_order using (order_id)
        where
            year(order_time) = 2021
            and month(order_time) = 10
            and start_time is null
    )
    and grade is not null
group by
    driver_id
WITH
    ROLLUP
ORDER BY
    driver_id IS NULL,
    driver_id

SELECT
    COALESCE(driver_id, '總體') AS driver_id,
    ROUND(AVG(grade), 1) AS grade
FROM ...
GROUP BY driver_id WITH ROLLUP

ORDER BY driver_id IS NULL, driver_id

ORDER BY CASE WHEN driver_id IS NULL THEN 1 ELSE 0 END, driver_id