如何 select 基于 SQL/php 中另一列的多个值的列中的单个值

Question

数据库不是我的。 结构是

fid| uid | value
 3 |  3  | spain
 3 |  5  | France
 2 |  3  | 45
 6 |  3  | male
 6 |  5  | female
 2 |  5  | 32

字段 ID 是另一个表中的主键，我想忘记。 我试图找到所有具有“西班牙”、“男性”值的 uid

我有以下工作。

SELECT uid 
FROM DATABASE
WHERE value IN ('spain', 'male') GROUP BY uid HAVING COUNT(*) >= 2

收获如下.. 我怎么会 select 男性，价值在 20-30 范围内的西班牙（即出生在西班牙的男性年龄在 20-30 岁之间？

万分感谢！！

Answer 1

使用自联接：

SELECT tland.uid
FROM `table` AS tland
INNER JOIN `table` AS tgender ON tland.uid = tgender.uid
INNER JOIN `table` AS tage ON tland.uid = tage.uid
WHERE tland.value = 'spain'
  AND tgender.value = 'male'
  AND 20 <= tage.value AND tage.value <= 30

Answer 2

你的桌子真的很乱。 你在价值中混合了不相关的东西。

尝试：

SELECT uid
FROM DATABASE a JOIN
  DATABASE b USING (uid)
WHERE a.value IN ('spain', 'male')
  AND b.value >= 20
  AND b.value <= 30
GROUP BY uid
HAVING COUNT(*) >= 2

请注意，我正在比较一个字符串和一个 integer。 您需要进行测试以查看其效果如何。

另外，我只是把西班牙和男性放在一起，但也许他们真的没有关系？

fid 是否确定值的类型？

尝试：

SELECT uid
FROM DATABASE country
JOIN DATABASE gender USING (uid)
JOIN DATABASE age USING (uid)
WHERE
  country.fid = 3 AND
  gender.fid = 6 AND
  age.fid = 2 AND
  county.value = 'spain' AND
  gender.value = 'male' AND
  age.value >= 20
  age.value <= 30
GROUP BY uid
HAVING COUNT(*) >= 2

此代码应该更可靠地工作。

Answer 3

这将起作用。

SELECT d1.uid FROM demo d1
INNER JOIN demo d2 ON d2.uid = d1.uid AND d2.fid = 6 AND d2.value = "Male"
INNER JOIN demo d3 ON d3.uid = d1.uid AND d3.fid = 3 AND d3.value = "Spain"
WHERE (d1.fid = 2 AND (d1.value BETWEEN 20 AND 30))

Answer 4

使您的语法尽可能接近它的样子，这可能会起作用：

SELECT uid
FROM database
WHERE value in ('spain', 'male') or convert(value, , SIGNED INTEGER) between 30 and 50
GROUP BY uid HAVING COUNT(*) >= 3

Answer 5

由于您的字段是这样映射的：

fid 3 = country
fid 2 = age
fid 6 = sex

您可以将该表转换为更具逻辑性的视图（在 UID 上编制索引）

(SELECT c.uid, c.country, a.age, s.sex FROM
   (SELECT uid, value AS country FROM maintable WHERE fid = 3) c INNER JOIN
   (SELECT uid, value AS age FROM maintable WHERE fid = 2) a ON c.uid = a.uid INNER JOIN
   (SELECT uid, value AS sex FROM maintable WHERE fid = 6) s ON c.uid = s.uid
) as X

一旦它在视图中，您就可以将您的数据视为常规表。 我假设您可能拥有超过 3 种类型的数据，因为在您的示例中 fid 最多为 6。

假设您已将其放入视图（称为 X）中，您可以这样做：

SELECT * FROM X
WHERE age BETWEEN 20 AND 30
   AND country = 'spain'
   AND sex = 'male'