未捕获的 PDOException：语法错误或访问冲突：1064 来自不正确的间距

Question

我从一行中收到两种不同类型的错误，我花了很长时间才找出错误所在。这是一个有趣的行为 php 在连接 MySql 查询语句时显示使用 bacticks 来分隔字符串。

$query='SELECT c.name as category_name, p.id, p.category_id, p.title, p.body, p.author, p.created_at
    FROM'.$this->table. ' p
    LEFT JOIN categories c ON p.category_id=c.id
    ORDER BY p.created_at DESC';

注意：FROM 和反引号之间没有 space。接下来的错误是

Fatal error: Uncaught PDOException: SQLSTATE[ 42000 ]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'p LEFT JOIN categories c ON p.category_id=c.id ORDER BY p.crea' at line 2 in C:\xampp\htdocs\php_REST_myblog\models\Post.php: 31 Stack trace:
#0 C:\xampp\htdocs\php_REST_myblog\models\Post.php(31): PDOStatement->execute()
#1 C:\xampp\htdocs\php_REST_myblog\api\posts\read.php(18): Post->read()
#2 {main } thrown in C:\xampp\htdocs\php_REST_myblog\models\Post.php on line 31

下一个变体是

  $query='SELECT c.name as category_name, p.id, p.category_id, p.title, p.body, p.author, p.created_at
    FROM '.$this->table. 'p
    LEFT JOIN categories c ON p.category_id=c.id
    ORDER BY p.created_at DESC';

注意反引号和 p 之间没有 space。数据库名称是 myblog，table 名称是 posts.The 错误是

Fatal error: Uncaught PDOException: SQLSTATE[ 42S02 ]: Base table or view not found: 1146 Table 'myblog.postsp' doesn't exist in C:\xampp\htdocs\php_REST_myblog\models\Post.php: 31 Stack trace:
#0 C:\xampp\htdocs\php_REST_myblog\models\Post.php(31): PDOStatement->execute()
#1 C:\xampp\htdocs\php_REST_myblog\api\posts\read.php(18): Post->read()
#2 {main } thrown in C:\xampp\htdocs\php_REST_myblog\models\Post.php on line
31

下面是正确的代码，多了两个 space。

$query='SELECT c.name as category_name, p.id, p.category_id, p.title, p.body, p.author, p.created_at
        FROM '.$this->table. ' p
        LEFT JOIN categories c ON p.category_id=c.id
        ORDER BY p.created_at DESC';

出了什么问题？

Answer 1

您的数据库和 table 名称将从 $this->table 添加，'p' 是它的别名。它们之间需要用space隔开，就像数据库名和FROM之间需要space一样。

未捕获的 PDOException：语法错误或访问冲突：1064 来自不正确的间距

Uncaught PDOException: Syntax error or access violation: 1064 from improper spacing

php

mysql

fatal-error

uncaught-exception