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Question

我的表名是ads，就像那样：

    id    ad_country          ad_gender     ad_birthday
     1     UK                  Male          2012-02-26
     2     sangapor            Female        2011-05-29
     3     UK                  Female        2010-04-12

我有两个下拉选择选项

   one  is to select country

和

    one is to select year

是否可以创建一个sql查询，该查询将结果关联到：

每个国家选择了多少男性，也选择了一年。每个国家和地区选择的女性人数也是多少 THX

我试过这个sql但是没有用。

    SELECT COUNT(ad_gender) AS male FROM ads  WHERE '".$_POST['country']."' = ad_country  AND ad_gender = Male AND '".$_POST['year']."' = '".$row2['ye']."'

请注意 $ row2 ['ye']来自$ sql2，如下所示

     SELECT ad_birthday,(substr(ad_birthday , 1, 4)) AS ye FROM ads

编辑我的帖子，因为我给的代码不多，这是我的新问题 my new post

Answer 1

我认为使用group by和having执行此操作的最简单方法是在查询中使用case。

SELECT  SUM(CASE WHEN ad_gender = 'Male' THEN 1 ELSE 0 END) TotalMale,
        SUM(CASE WHEN ad_gender = 'Female' THEN 1 ELSE 0 END) TotalFemale
FROM    ads
WHERE   ad_country = 'countryHere' AND
        YEAR(DATE(ad_birthday)) = yearHere

SQLFiddle Demo

还有一件事，永远不要将用户的值直接传递给你的sql语句，因为 SQL Injection 可能容易受到攻击。使用 PDO 或 MYSQLI

使用PDO扩展的示例：

<?php

     $query = "    SELECT   SUM(CASE WHEN ad_gender = 'Male' THEN 1 ELSE 0 END) TotalMale,
                           SUM(CASE WHEN ad_gender = 'Female' THEN 1 ELSE 0 END) TotalFemale
                   FROM     ads
                   WHERE    ad_country = ? AND
                            YEAR(DATE(ad_birthday)) = ?"

    $country = 'UK';
    $year = 2012;
    $dbh = new PDO('mysql:host=localhost;dbname=test;charset=utf8', $user, $pass);
    $dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
    $stmt = $dbh->prepare($query);
    $stmt->bindParam(1, $country);
    $stmt->bindParam(2, $year);
    if ($stmt->execute()) 
    {
         while ($row = $stmt->fetch()) 
         {
              print_r($row);
         }
    }

?>

这将允许您插入带单引号的记录。

Answer 2

select ad_country, count(case when ad_gender = 'male' then 1 end) male, 
count(case when ad_gender = 'female' then 1 end) female, year(ad_birthday) year
from ads
group by ad_country, year(ad_birthday)

Answer 3

这应该是一个非常简单的执行查询，所以我想知道为什么它不适合你。到目前为止你尝试了什么？

select
  ad_country as country,
  YEAR(ad_birthday) as year,
  ad_gender as gender,
  count(id) as count
from ads
where ad_country in ('/* your country params here*/')
group by ad_country, year, ad_gender
having YEAR(ad_birthday) in ('/* your year params here*/')

您不需要第二个SQL查询只是为了将日期部分拉出表格 - 请使用built-in SQL date & time functions。

此外，这是偏离主题，但您发布的代码看起来像内联SQL。请改用parameterized queries，否则您很容易受到SQL注入攻击。

通过sql过滤结果

3 个答案:

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