Question

我正在执行搜索功能，我有联系人组和语言，

这是mysql查询：

$sql = "SELECT * FROM contact where isdeleted = 0  ";

      if ($language !="" && $language !="Empty" ){

                $language_exp = explode(',', $language);
     $sql .= " INNER JOIN contactlanguage ON contact.id = contactlanguage.contactid
INNER JOIN language ON contactlanguage.languageid = language.id AND language.language in ('".implode("', '", $language_exp)."')"; 

            }


    if ($contactgroup !="" && $contactgroup !="Empty" ){



    $contactgroup_exp = explode(',', $contactgroup);
    $sql .= " AND contactgroup in ('".implode("', '", $contactgroup_exp)."')";

    }

如果我只选择语言，那么首先会有三种情况，它会像这样执行查询

它不起作用

SELECT * FROM contact where isdeleted = 0 INNER JOIN contactlanguage ON contact.id = contactlanguage.contactid INNER JOIN language ON contactlanguage.languageid = language.id AND language.language in ('English', '')

如果没有选择语言，则仅选择其工作的联系人组，

SELECT * FROM contact where isdeleted = 0 AND contactgroup in ('Contactgroup1', '')

第三种情况，如果我选择语言和联系人组，它不起作用

SELECT * FROM contact where isdeleted = 0  INNER JOIN contactlanguage ON contact.id = contactlanguage.contactid INNER JOIN language ON contactlanguage.languageid = language.id AND language.language in ('English', '') AND contactgroup in ('Contactgroup1', '')

任何人都可以指导我如何执行案例1和案例3的查询，谢谢

Answer 1

JOIN查询错误，您需要将JOIN语句之后的where条件移动为

SELECT * FROM contact 
INNER JOIN contactlanguage ON contact.id = contactlanguage.contactid
INNER JOIN language ON contactlanguage.languageid = language.id
where 
isdeleted = 0   
AND language.language in ('English', '')

Answer 2

查询错误。您必须首先添加join语句，然后添加where

SELECT * FROM contact INNER JOIN contactlanguage ON contact.id = ... where isdeleted = 0

MYSQL查询连接问题

2 个答案: