Php 在mysql连接查询中使用变量

在这个查询中，当我手动放置cities.city_id的值时，它可以正常工作，但当我使用$adcity之类的变量传递时，它不会显示任何输出。有谁能帮我在这个查询中如何使用变量吗

有人能在这方面帮助我吗

$sql = 'SELECT advertisments.ad_id,
         advertisments.ad_title, 
        advertisments.ad_title_slug,
         advertisments.ad_type, 
        advertisments.last_date,
         organizations.organization_logo, 
        cities.city_id, 
        cities.city_name, 
        newspapers.newspaper_logo, 
        newspapers.newspaper_name
FROM advertisments, organizations, cities, newspapers
WHERE advertisments.organization_id = organizations.organization_id
AND advertisments.city_id = cities.city_id
AND advertisments.newspaper_id = newspapers.newspaper_id
AND ad_type = "Admissions"
AND cities.city_id = "$adcity"
        ORDER BY ad_id DESC 
        LIMIT 10';
        $open_admissions = mysql_query($sql);

现在你试试看

$sql = 'SELECT advertisments.ad_id,
         advertisments.ad_title, 
        advertisments.ad_title_slug,
         advertisments.ad_type, 
        advertisments.last_date,
         organizations.organization_logo, 
        cities.city_id, 
        cities.city_name, 
        newspapers.newspaper_logo, 
        newspapers.newspaper_name
FROM advertisments, organizations, cities, newspapers
WHERE advertisments.organization_id = organizations.organization_id
AND advertisments.city_id = cities.city_id
AND advertisments.newspaper_id = newspapers.newspaper_id
AND ad_type = "Admissions"
AND cities.city_id = "'.$adcity.'"
        ORDER BY ad_id DESC 
        LIMIT 10';
        $open_admissions = mysql_query($sql);

只要加上

cities.city_id=“”.$adcity.”“

像这样

希望它对你有用。如果它不起作用。告诉我

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谢谢

首先在phpmyadmin或cpanel中运行您的查询。检查它是否返回一些行或行not@AghaUmairAhmed谢谢，让我检查一下。你使用的是非常陈旧和不安全的语法。考虑使用MySqLi。@ SuryaS感谢提醒……“或死亡（MyQuLyError（））给你什么-并且注意这套功能（MySQL）是deprecatedShamsher Kaim k感谢你的帮助，我已经解决了我的问题，但你评论相同的解决方案，所以接受它。