PHP mysql使用关键字搜索多个表

Question

我的数据库中有三个表：

messages
topics
comments

每个表格都有两个字段，分别称为“内容”和“标题”。我希望能够在我的 sql 语句中使用“Like”来查看“messages.content”、“messages.title”、“topics.content”、“topics.title”、“cmets.content”和“cmets”。标题'使用关键字。

到目前为止，我的查询只能从一个表中找到结果：

mysql_query("SELECT * FROM messages 
WHERE content LIKE '%" . $keyword . "%' 
OR title LIKE '%" . $keyword ."%'");

我也想知道，一旦我从多个表中获取结果，我怎么知道哪个表的结果是什么？

任何帮助将不胜感激！

Answer 1

您可能正在寻找的是 UNION 命令：

SELECT id, 'messages' as 'table' FROM messages 
  WHERE content LIKE '%keyword%' 
    OR title LIKE '%keyword%'
UNION
SELECT id, 'topics' as 'table' FROM topics
  WHERE content LIKE '%keyword%' 
    OR title LIKE '%keyword%'
UNION
SELECT id, 'comments' as 'table' FROM comments
  WHERE content LIKE '%keyword%' 
    OR title LIKE '%keyword%'

Answer 2

HTML 搜索表单：

<div class="header_top_right">
    <form action="search.php" method="GET" class="search_form">
        <input type="text" placeholder="Text to Search.." name="search">
        <input type="submit" class="btn btn-default" value="">
    </form>
</div>

搜索.php：

<?php
    if (isset($_GET['search']) || !empty($_GET['search'])) {
        $search = mysqli_real_escape_string($db->link, $fm->validation($_GET['search']));
    }
    else{
        header("Location:404.php");
    }
?>
<?php
    $query = "SELECT * FROM news_post WHERE title LIKE '%$search%' OR body LIKE '%$search%' OR tags LIKE '%search%'";
    $post = $db->select($query);
    if ($post) {
        while ($result = $post->fetch_assoc()) {
            echo"Database data like, $result['title']";
        }
    }
    else{
        echo "result Not found";
    }

在 search.php 中包含 database.php

class Database{
    public function select($query){
        $result = $this->link->query($query) or die($this->link->error.__LINE__);
        if($result->num_rows > 0){
            return $result;
        }
        else {
            return false;
        }
    }
}
$db = new Database();

Answer 3

$query = "(SELECT content, title, 'msg' as type FROM messages WHERE content LIKE '%" . 
           $keyword . "%' OR title LIKE '%" . $keyword ."%') 
           UNION
           (SELECT content, title, 'topic' as type FROM topics WHERE content LIKE '%" . 
           $keyword . "%' OR title LIKE '%" . $keyword ."%') 
           UNION
           (SELECT content, title, 'comment' as type FROM comments WHERE content LIKE '%" . 
           $keyword . "%' OR title LIKE '%" . $keyword ."%')";

mysql_query($query);

因此，您从所有三个表中获取结果，并且您可以通过查看其 type 值来确定哪一行来自哪个表。

Answer 4

在您使用的其他表中进行两次搜索：

SELECT `categories`.`title`, `posts`.`title` WHERE `categories`.`title` LIKE {$a} OR `posts`.`title` LIKE {$a}

CATEGORIES 和 POSTS 是数据库的表。