查询花费很长时间执行

我有以下查询，我正在使用这两个运算符来获取具有特定数字之间的年龄的记录，但查询花了很多时间来显示结果，其鸭舌超过5分钟仍运行查询花费很长时间执行

SELECT 
    *, 
    (SELECT COUNT(*) 
    FROM users 
    WHERE 
    1=1 OR 
    LOWER(age) BETWEEN 18 AND 20 OR 
    LOWER(age) BETWEEN 20 AND 25 OR 
    LOWER(age) BETWEEN 25 AND 30 OR 
    LOWER(age) BETWEEN 30 AND 35 
) AS totalcount 
FROM users, states, countries, user_types, media 
WHERE 
    users.id_user_type = user_types.id AND 
    users.id_state = states.id AND 
    users.id_country = countries.id AND 
    media.id_user = users.id AND 
    media.profile_photo = 1 AND 
    users.id_user_type = 3 OR 
    LOWER(age) BETWEEN 18 AND 20 OR 
    LOWER(age) BETWEEN 20 AND 25 OR 
    LOWER(age) BETWEEN 25 AND 30 OR 
    LOWER(age) BETWEEN 30 AND 35 
ORDER BY users.id

令人不安的部分是：使用or条款你有（它没有意义）

LOWER(age) BETWEEN 18 AND 20 OR 
LOWER(age) BETWEEN 20 AND 25 OR 
LOWER(age) BETWEEN 25 AND 30 OR 
LOWER(age) BETWEEN 30 AND 35

来源

2014-11-02 voyeger

你是什么试图用这个查询来检索？ – 2014-11-02 12:57:24

你怎么得出这样的结论：查询的那一部分是令人不安的部分？ – Guffa 2014-11-02 12:57:29

避免。你的查询可能做了很多CROSS JOIN操作，这就是为什么它需要很长时间（你的结果集很大）。

select *, 
     (
      select count(*) 
       from users 
      where 1=1 
       or lower(age) between 18 and 20 
       or lower(age) between 20 and 25 
       or lower(age) between 25 and 30 
       or lower(age) between 30 and 35 
     ) as totalcount 
    from users, states, countries, user_types, media 
    where users.id_user_type = user_types.id 
    and users.id_state = states.id 
    and users.id_country = countries.id 
    and media.id_user = users.id 
    and media.profile_photo = 1 
    and users.id_user_type = 3 
    order by users.id

此外，目前还不清楚你试图用这个查询来完成什么。

回答这些问题可以帮助我们来帮您：

有什么age列类型
你到底是从内部查询

来源

2014-11-02 12:59:17

WHERE 1 = 1'和所有其他'BETWEEN'语句怎么样？为什么使用LOWER年龄），年龄是一个字符串吗？为什么要把它和数字比较呢？我认为你应该解决这些问题，当它说“它没有意义”时。 – wolfgangwalther 2014-11-02 13:02:21

你or语句解析不正确期待什么。您需要括号：

FROM users, states, countries, user_types, media 
WHERE (users.id_user_type = user_types.id AND 
     users.id_state = states.id AND 
     users.id_country = countries.id AND 
     media.id_user = users.id AND 
     media.profile_photo = 1 AND 
     (users.id_user_type = 3 OR 
     LOWER(age) BETWEEN 18 AND 20 OR 
     LOWER(age) BETWEEN 20 AND 25 OR 
     LOWER(age) BETWEEN 25 AND 30 OR 
     LOWER(age) BETWEEN 30 AND 35 
     )

书面，查询所要做的五个表中一个完整的笛卡尔乘积，然后做一些怪异的过滤。

如果您使用适当的join语法，这基本上是一个非问题。简单的规则：切勿在from子句中使用逗号。

另外，查询似乎没有意义。为什么要将age作为字符串存储（如使用lower()建议的那样？那么，为什么要将这些与整数进行比较？为什么要将连续范围分成四个不同的比较，而不是仅仅说age between 18 and 35？

来源

2014-11-02 13:41:47

查询花费很长时间执行

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