php - mysql 语法错误，无法检测到它的位置 :

Question

作为商场背景:

这是一个查询，我在其中查找字符串中的关键字。

我用“”空格分解字符串:

$words = explode(" ", $searchstring); 

然后我用逗号分隔它们:

$commaSeparatedString = implode(", ", $words); 

然后我执行查询:

$searchQuery = sprintf("SELECT * FROM solution T1 join solution_tags_intermediate T2
                        on T1.ID_SOLUTION = T2.ID_SOLUTION
                        join solution_tags T3 on T2.ID_SOLUTION_TAGS = T3.ID_SOLUTION_TAGS
                        WHERE T3.SOLUTION_TAGS_NAME IN '%s'", $commaSeparatedString);

我执行查询:

$resultSet = $DBConnect->query($searchQuery);

我收到以下错误:

Warning: Creating default object from empty value in C:\wamp\www\helpdesk\index.php on line 21

Fatal error: Call to undefined method stdClass::fetch_assoc() in C:\wamp\www\helpdesk\index.php on line 27 

第 21 行是:

if($resultSet->num_rows = 0){ /*more code here*/}

第 27 行是:

while($tableData = $resultSet->fetch_assoc()){/*print some stuff here*/}

据我所知，这是查询的正确语法，但 phpmyadmin 说它不是。这是我实际执行的查询:

SELECT * FROM solution T1 join solution_tags_intermediate T2 
on T1.ID_SOLUTION = T2.ID_SOLUTION 
join solution_tags T3 
on T2.ID_SOLUTION_TAGS = T3.ID_SOLUTION_TAGS 
WHERE T3.SOLUTION_TAGS_NAME IN 'internet, renweb'

phpmyadmin 抛出的错误是:

 #1064 - You have an error in your SQL syntax; 
 check the manual that corresponds to your MySQL server version 
 for the right syntax to use near ''internet, renweb' LIMIT 0, 30' at line 1

我做错了什么？我已经在这个项目上工作了 8 个多小时，我知道这可能很简单，但我就是无法弄清楚问题是什么。

Answer 1

试试这个查询:

  SELECT * FROM solution T1 join solution_tags_intermediate T2 
    on T1.ID_SOLUTION = T2.ID_SOLUTION 
    join solution_tags T3 
    on T2.ID_SOLUTION_TAGS = T3.ID_SOLUTION_TAGS 
    WHERE T3.SOLUTION_TAGS_NAME IN ('internet', 'renweb')

你这里也有问题:

if($resultSet->num_rows = 0){ /*more code here*/}

你需要像这样使用比较符号==:

if($resultSet->num_rows == 0){ /*more code here*/}