SQL Case When语句对多个表上的行进行计数

SELECT
    COUNT(CASE WHEN condition1 THEN column_name END) AS count1,
    COUNT(CASE WHEN condition2 THEN column_name END) AS count2,
    ...
FROM
    table_name1
    JOIN table_name2 ON join_condition
WHERE
    where_condition;

SELECT
    COUNT(CASE WHEN order_status = 'Pending' THEN 1 END) AS pending_count,
    COUNT(CASE WHEN order_status = 'Completed' THEN 1 END) AS completed_count,
    COUNT(CASE WHEN order_status = 'Cancelled' THEN 1 END) AS cancelled_count
FROM
    orders
    JOIN products ON orders.product_id = products.product_id
WHERE
    products.product_name = 'Product A';