Mysql 使用内部选择的查询计数

在输出不太正确的地方使用内部选择时，我遇到了一个问题。任何帮助都将不胜感激

这是我的例子

这是我正在使用的查询

SELECT 
t.event as event_date,
count((
    SELECT
        count(s.id)
    FROM mytable s
    WHERE s.type = 2 AND s.event = event_date
)) AS type_count,
count((
    SELECT
        count(s.id)
    FROM mytable s
    WHERE s.type != 3 AND s.event = event_date
)) as non_type_count
FROM mytable t
WHERE t.event >= '2013-10-01' AND t.event <= '2013-10-08'
GROUP BY t.event

所以，如果你看看我试图使用的查询，我基本上是 尝试查询日期范围内的表，然后使用内部选择 获取与类型匹配的行。 提前感谢您的帮助。

您正在计算计数选择计数。。。。试试这个：

SELECT 
    t.event as event_date,
    (SELECT
            count(s.id)
        FROM mytable s
        WHERE s.type = 2 AND s.event = event_date
    ) AS type_count,
    (SELECT
            count(s.id)
        FROM mytable s
        WHERE s.type != 3 AND s.event = event_date
    ) as non_type_count
FROM mytable t
WHERE t.event >= '2013-10-01' AND t.event <= '2013-10-08'
GROUP BY t.event

您正在计数计数选择计数。。。。试试这个：

SELECT 
    t.event as event_date,
    (SELECT
            count(s.id)
        FROM mytable s
        WHERE s.type = 2 AND s.event = event_date
    ) AS type_count,
    (SELECT
            count(s.id)
        FROM mytable s
        WHERE s.type != 3 AND s.event = event_date
    ) as non_type_count
FROM mytable t
WHERE t.event >= '2013-10-01' AND t.event <= '2013-10-08'
GROUP BY t.event

---

可以使用条件聚合简化位并排除子选择：

SELECT 
    t.event as event_date,
    SUM(t.type = 2) AS type_count,
    SUM(t.type != 3)AS non_type_count
FROM mytable t
WHERE t.event >= '2013-10-01' AND t.event <= '2013-10-08'
GROUP BY t.event

演示：

---

这在MySQL中有效，因为表达式返回1或0表示真/假。在其他数据库中，当type=2时，您可以通过SUMCASE实现相同的功能，然后1-END可以简化位并使用条件聚合排除子选择：

SELECT 
    t.event as event_date,
    SUM(t.type = 2) AS type_count,
    SUM(t.type != 3)AS non_type_count
FROM mytable t
WHERE t.event >= '2013-10-01' AND t.event <= '2013-10-08'
GROUP BY t.event

演示：

这在MySQL中有效，因为表达式返回1或0表示真/假。在其他数据库中，当type=2然后1 END时，您可以通过SUMCASE实现相同的功能。请尝试以下方法：

SELECT 
    t.event as event_date,
    SUM( case when type = 2 then 1 else 0 end )
       AS type_count,
    SUM( case when type != 3 then 1 else 0 end )
       as non_type_count
FROM mytable t
WHERE t.event >= '2013-10-01' AND t.event <= '2013-10-08'
GROUP BY t.event

演示：->

尝试以下方法：

SELECT 
    t.event as event_date,
    SUM( case when type = 2 then 1 else 0 end )
       AS type_count,
    SUM( case when type != 3 then 1 else 0 end )
       as non_type_count
FROM mytable t
WHERE t.event >= '2013-10-01' AND t.event <= '2013-10-08'
GROUP BY t.event

---

演示：->

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