集结SQL结果，两个表，然后汇总结果

Question

使用MSSQL

我有用户表，和产品表它们认购。这些订阅是免费（F）或付费（P）。我已经加入了这些表格，使用case语句将F/P值转换为数字，然后通过用户ID汇总这些值，想法是任何只有免费账户的人都会有0的总和，至少有一个付费帐户价值1或更高。我用下面的远获得这样的：

SELECT t1.user_id, SUM(
    CASE 
     WHEN t2.free_paid = 'P' 
      THEN 1 
     ELSE 0 
    END) as highest 
FROM users t1 INNER JOIN accounts t2 
    ON t1.user_id = t2.user_id 
WHERE t2.account = 'A' 
GROUP BY t1.user_id 
ORDER BY t1.user_id 

这将产生类似的结果：

755 2 
1259 2 
2031 1 
3888 0 

这意味着所有的，但3888至少有一个支付账户。

但是现在我想简单地添加这些数据来获得我们的两个值，一个是至少有一个付费账户的用户数（例如3个），另一个是只有免费账户的用户数例）。

我试过声明两个变量，例如： @free和@paid，并使用case语句将这些值包装到子查询中，然后将其作为子查询添加到这些值中，但无法运行。

任何想法？

Answer 1

重新使用查询从这个问题您可以创建一个CTE（或子查询），并汇总结果：

;WITH CTE_UserAccounts AS (
    SELECT t1.user_id, SUM(
     CASE 
      WHEN t2.free_paid = 'P' 
       THEN 1 
      ELSE 0 
     END) as highest 
    FROM users t1 INNER JOIN accounts t2 
     ON t1.user_id = t2.user_id 
    WHERE t2.account = 'A' 
    GROUP BY t1.user_id 
) 
SELECT 
    COUNT(CASE WHEN highest > 0 THEN 1 END) AS [Paid], 
    COUNT(CASE WHEN highest = 0 THEN 1 END) AS [Free] 
FROM 
    CTE_UserAccounts; 

Answer 2

SELECT 
COUNT(DISTINCT CASE WHEN t2.free_paid = 'P' THEN t1.user_id END) as atleast_one_paid, 
COUNT(DISTINCT CASE WHEN t2.free_paid <> 'P' THEN t1.user_id END) as onlyfree 
FROM users t1 
INNER JOIN accounts t2 ON t1.user_id = t2.user_id 
WHERE t2.account = 'A' 

Answer 3

你可以只环绕你的原始查询和概括起来

SELECT SUM (case when highest > 0 THEN 1 else 0 END) as UsersWithPaidAccount, 
SUM (case when highest = 0 THEN 1 else 0 END) as UsersWithOnlyFreeAccount 
FROM (SELECT t1.user_id, SUM(
    CASE 
     WHEN t2.free_paid = 'P' 
      THEN 1 
     ELSE 0 
    END) as highest 
FROM users t1 INNER JOIN accounts t2 
    ON t1.user_id = t2.user_id 
WHERE t2.account = 'A' 
GROUP BY t1.user_id) 
as DerivedTable