在一个查询中结合两个计数与连接

Question

好的 - 希望有人可以帮助，因为我在这里挣扎。已尝试使用sum（case when），count（*），子查询没有成功。 基本上我有两个查询，我试图合并成一个，由相同的参数分组。查询：

查询1：

SELECT 
u.username, 
count(*) as 'Total' 

FROM log1 L1 
JOIN users u on u.userref = L1.userref 
WHERE L1.date between @FromDate and @ToDate 
GROUP BY u.username 
ORDER BY u.username 

问题2：

SELECT 
u.username, 
count(*) as 'Total' 

FROM log2 L2 
LEFT JOIN users u on u.userref = L2.userref 
WHERE L2.date between @FromDate and @ToDate and L2.message like '%None%' 
GROUP BY u.username 
ORDER BY u.username 

我想是使用用户名柱（u.username），示出的结果的列的单个查询查询1的结果以及显示查询2的结果的列。任何帮助感谢！

Answer 1

你可以把一个case语句count函数里面只能算当某些条件得到满足：

SELECT u.username, 
     Total = COUNT(*), 
     Total2 = COUNT(CASE WHEN L.message LIKE '%None%' THEN 1 END) 
FROM log1 AS L 
     JOIN users AS u 
      ON u.userref = L.userref 
WHERE L.date BETWEEN @FromDate and @ToDate 
GROUP BY u.username 
ORDER BY u.username; 

值得注意的是：

• BETWEEN can cause problems, especially when working with dates
• Using string literals for column aliases is on the deprecation list

编辑

完全错过了，你有两个单独的日志表：

SELECT u.username, 
     Total = COUNT(Count1), 
     Total2 = COUNT(Count2) 
FROM ( SELECT l.UserRef, Count1 = 1, Count2 = NULL 
      FROM log1 AS L 
      WHERE L.date BETWEEN @FromDate and @ToDate 
      UNION ALL 
      SELECT l.UserRef, Count1 = NULL, Count2 = 1 
      FROM log2 AS L 
      WHERE L.date BETWEEN @FromDate and @ToDate 
      AND  L.message LIKE '%None%' 
     ) AS l 
     JOIN users AS u 
      ON u.userref = L.userref 
GROUP BY u.username 
ORDER BY u.username; 

Answer 2

  SELECT X.USERNAME,X.TOTAL,Y.TOTAL 
    FROM(SELECT 
      u.username, 
      count(*) as 'Total' 
      FROM log1 L1 
      JOIN users u on u.userref = L1.userref 
      WHERE L1.date between @FromDate and @ToDate 
      GROUP BY u.username 

      ) as x 
INNER JOIN 
      (
      SELECT 
      u.username, 
      count(*) as 'Total' 
      FROM log2 L2 
      LEFT JOIN users u on u.userref = L2.userref 
      WHERE L2.date between @FromDate and @ToDate and L2.message like '%None%' 
      GROUP BY u.username 
      ) AS Y ON Y.USERNAME = X.USERNAME