在一个查询中将两个计数与连接结合起来

Question

好的 - 希望有人能在我在这里苦苦挣扎时提供帮助。已尝试使用 sum(case when)、count(*)、子查询，但均未成功。 本质上，我有两个查询我试图合并为一个，按相同的参数分组。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

查询 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

我想要的是一个带有用户名列 (u.username) 的单个查询，一列显示查询 1 的结果，一列显示查询二的结果。任何帮助表示赞赏！

Answer 1

您可以在 count 函数中放置一个 case 语句，以便仅在满足某些条件时才进行计数：

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;

注意：

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

编辑

完全错过了您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