1

我有以下查询：

$query = <<<SQL
SELECT
      year,  
      count(*) AS `counter`, 
      GROUP_CONCAT(team) AS `team_list` 
    FROM
      team_list 
    WHERE year IS NOT NULL              
SQL;

if (!empty($sql)) { //$sql is an array of SQL WHERE statements "a IN (a,b,c)"
    $query .= ' AND ' . implode(' AND ', $sql);
} 
    

    $query .= 'GROUP BY year ORDER BY year';
    
    
    /////////////////////////////
    //EXECUTING THE QUERIES
    /////////////////////////////
    
    //Filter count to know how many 's' variable have to be bind to the prepared statement
    $filterCount = count($teams) + count($countries) + count($years) + count($rankings); //These are my ajax elements that are also used in the $sql variable
        
    //Data query
    $queryYears = $connection->prepare($query);
    $queryYears->bind_param(str_repeat('s', $filterCount), ...$teams, ...$countries, ...$years, ...$rankings);
    $queryYears-> execute();

这一切都很好！

问题

但是，一旦我尝试SET SESSION group_concat_max_len = 1000000;在查询语句的开头输入，我就会收到以下错误：

Fatal error: Uncaught Error: Call to a member function bind_param() on boolean

我知道我的查询现在有问题，但是当将它复制粘贴到我的 DBMS 时，可以毫无问题地执行查询。

我在这里做错了什么？

4

1 回答 1

3

您的问题是您试图一次执行两个查询，并且mysqli::prepare不支持该查询，因此它失败并返回 false。相反，首先将变量集作为单独的查询运行：

$connection->query("SET SESSION group_concat_max_len = 1000000;") or die($connection->error);
$queryYears = $connection->prepare($query) or die($connection->error);
// etc.

请注意，您应该检查呼叫的状态，就像我在上面的代码中所做的那样。

于 2019-05-07T05:02:28.453 回答