SQL 组合多个 SELECT 语句

Question

我正在尝试构建一个 SQLite 查询，该查询将从单个表中收集统计信息。

该表包含一个日志，每天有几个条目。我需要在搜索参数中为每一天获取一个单独的行，然后使用某些布尔值编译这些日期内的行总数。

这是我目前的查询：

SELECT DATE(DateTime) AS SearchDate,
     (SELECT COUNT() AS Total
                FROM CallRecords
                WHERE DATE(DateTime)
                BETWEEN '2017-08-27' AND '2017-09-02'
                GROUP BY DATE(DateTime)
                ORDER BY Total DESC) AS Total,
    (SELECT COUNT() AS Total
                FROM CallRecords
                WHERE NoMarket = 1
                AND DATE(DateTime)
                BETWEEN '2017-08-27' AND '2017-09-02'
                GROUP BY DATE(DateTime)
                ORDER BY Total DESC) AS NoMarkets,
    (SELECT COUNT() AS Total
                FROM CallRecords
                WHERE Complaint = 1
                AND DATE(DateTime)
                BETWEEN '2017-08-27' AND '2017-09-02'
                GROUP BY DATE(DateTime)
                ORDER BY Total DESC) AS Complaints,
    (SELECT COUNT() AS Total
                FROM CallRecords
                WHERE Voicemail = 1
                AND DATE(DateTime)
                BETWEEN '2017-08-27' AND '2017-09-02'
                GROUP BY DATE(DateTime)
                ORDER BY Total DESC) AS Voicemails
FROM CallRecords
WHERE DATE(DateTime) BETWEEN '2017-08-27' AND '2017-09-02'
GROUP BY SearchDate

还有输出：

8/28/2017   175 27      11
8/29/2017   175 27      11
8/30/2017   175 27      11
8/31/2017   175 27      11
9/1/2017    175 27      11

如您所见，它正确获取了每个单独的日期，但列的总数不正确。

显然，我在查询中遗漏了一些内容，但我不确定在哪里。有没有更好的方法来执行这个查询？

编辑：我在这里查看了其他几个标题几乎相同的问题，但我没有找到与我正在寻找的类似的东西。大多数似乎比我想要完成的要复杂得多。

Answer 1

您的CallRecords 表中似乎有一堆乱七八糟的列，名称如Complaint 和Voicemail，每个列都对调用进行分类。

看起来这些列在相关时的值为 1。

所以这个查询应该会对你有所帮助。

SELECT DATE(DateTime) AS SearchDate,
       COUNT(*) AS Total,
       SUM(NoMarket = 1) AS NoMarkets,
       SUM(Complaint = 1) AS Complaints,
       SUM(Voicemail = 1) AS Voicemails
  FROM CallRecords
 WHERE DateTime >=  '2017-08-27'
   AND DateTime <   '2017-09-02' + INTERVAL 1 DAY
 GROUP BY DATE(DateTime)

为什么会这样？因为在 MySQL 中，像 Voicemail = 1 这样的布尔表达式在其为真时具有值 1，而在其为假时具有 0。您可以很好地总结这些值。

为什么它比你拥有的更快？因为DATE(DateTime) BETWEEN this AND that 不能利用DateTime 上的索引。

为什么您的日期范围结束时正确？因为DateTime < '2017-09-02' + INTERVAL 1 DAY 提取所有记录，直到（但不包括）午夜，在您的日期范围之后。

如果您使用的是 Sqlite，则需要 AND DateTime < date('2017-09-02', '+1 day')。 + INTERVAL 1 DAY 的内容略有不同。

Answer 2

SELECT DATE(DateTime) AS SearchDate, Total, NoMarkets, Complaints, Voicemails FROM
 (SELECT COUNT() AS Total FROM CallRecords) CR
 JOIN
(SELECT COUNT() AS NoMarkets FROM CallRecords WHERE NoMarket = 1) NM
 ON CR.DateTime = NM.DateTime
 JOIN
(SELECT COUNT() AS Complaints FROM CallRecords WHERE Complaint = 1) C
 ON NM.DateTime = C.DateTime
 JOIN
(SELECT COUNT() AS Voicemails FROM CallRecords WHERE Voicemail = 1) VM
 ON C.DateTime = VM.DateTime
 JOIN CallRecords CLR ON VM.DateTime=CLR.DateTime WHERE DATE(CLR.DateTime) >= '2017-08-27' AND DATE(CLR.DateTime) <= '2017-09-02'GROUP BY SearchDate;

这可能会正确输出。

Answer 3

你可以这样做，虽然我是用 SQL server 写的

SELECT DATE(DateTime) AS SearchDate,
    COUNT() AS TOTAL,
    SUM(CASE WHEN NoMarket = 1 THEN 1 ELSE 0 END) AS NoMarkets,
    SUM(CASE WHEN Complaint = 1 THEN 1 ELSE 0 END) AS Complaints,
    SUM(CASE WHEN Voicemail = 1 THEN 1 ELSE 0 END) AS Voicemails
FROM CallRecords
WHERE DATE(DateTime) BETWEEN '2017-08-27' AND '2017-09-02'
GROUP BY SearchDate