Question

我有查询

SELECT all_users,
       employed_users,
       SUM(CASE WHEN (employment_one_terminated = 1 OR employment_two_terminated = 1) THEN 1 ELSE 0 END) AS unemployed_users
    FROM users
       WHERE status = 1

我在网页上添加了过滤器unemployed_min和unemployed_max数字，有没有办法在MySQL中过滤而不涉及PHP当你在页面上选择时说

unemployed_min = 1
unemployed_max = 5

当我做的时候

SELECT all_users,
       employed_users,
       SUM(CASE WHEN (employment_one_terminated = 1 OR employment_two_terminated = 1) THEN 1 ELSE 0 END) AS unemployed_users
    FROM users
       WHERE status = 1
         AND unemployed_users > 1 AND unemployed_users < 5

或

SELECT all_users,
       employed_users,
       SUM(CASE WHEN (employment_one_terminated = 1 OR employment_two_terminated = 1) THEN 1 ELSE 0 END) AS unemployed_users
    FROM users
       WHERE status = 1
         AND SUM(CASE WHEN (employment_one_terminated = 1 OR employment_two_terminated = 1) THEN 1 ELSE 0 END) > 1 
         AND SUM(CASE WHEN (employment_one_terminated = 1 OR employment_two_terminated = 1) THEN 1 ELSE 0 END) < 5

不起作用

修改它说“无效使用群组功能”但是我不使用群组声明

Answer 1

您正在寻找having子句，因为您想要对聚合表达式进行过滤：

SELECT all_users,
       employment_terminated,
       unemployment_collected,
       SUM(CASE WHEN (employment_one_terminated = 1 OR employment_two_terminated = 1) THEN 1 ELSE 0 END) AS unemployed_users
FROM users
WHERE status = 1
HAVING unemployed_users > 1 AND unemployed_users < 5;

Answer 2

您的查询存在严重的分组问题。您正在使用聚合函数，而不是在选择一些字段时按任何字段进行分组。这意味着您只会在all_users和employed_users中获得包含不可预测值的一行。

首先，您必须定义正确的分组（可能是这个？）

GROUP BY all_users, employed_users

然后，如果您需要过滤组，可以使用HAVING子句：

HAVING unemployed_users > 1 AND unemployed_users < 5

您也可以通过这种方式简化SUM：

SUM(employment_one_terminated = 1 OR employment_two_terminated = 1)

如果这些是布尔值，您甚至可以删除= 1。

最终查询应该与此非常相似：

SELECT all_users, employed_users,
  SUM(employment_one_terminated OR employment_two_terminated) AS unemployed_users
FROM users
WHERE status = 1
GROUP BY all_users, employed_users
HAVING unemployed_users > 1 AND unemployed_users < 5

MySQL使用WHERE条件的结果

2 个答案: