在一个查询中将两个计数与联接组合 [英] Combining two counts with joins in one query

问题描述

确定 - 希望有人能帮助我在这里奋斗。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，我试图组合成一个，按相同的参数分组。查询：

Ok - hoping someone can help as I'm struggling here. Have tried using sum(case when), count(*), subqueries with no success. Essentially I have two queries I am trying to combine into one, grouped by the same parameter. The queries:

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

我想是一个单一查询，用户名列（u.username），一列显示查询1的结果，一列显示查询二的结果。任何帮助赞赏！

What I would like is a single query with a username column (u.username), a column showing the results of query 1, and a column showing the results of query two. Any help appreciated!

推荐答案

您可以将count语句放在count函数中， p>

You can put a case statement inside the count function to only count when certain criteria is met:

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可能会导致问题，特别是处理日期


• 对列别名使用字符串文字位于弃用列表

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

EDIT

完全错过了有两个单独的日志表：

Completely missed that you had two separate log tables:

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;

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