php - 如何将两个MySQL连接合并为一个MySQL连接？

Question

我在一个 .php 文件中对同一个数据库有两个 MySQL 连接。

第二个连接基于第一个连接的结果。

如何将两个连接合并为一个？请帮助并教我如何修改它？

第一次连接:

<?php
header('Content-Type: text/html; charset=utf-8');

$servername = "localhost";
$username = "abcabc";
$password = "12341234";
$dbname = "abc1234";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
$conn->set_charset("utf8");
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

// Logic data
$previous_page = ($_GET['crno'] - 1);
$next_page = ($_GET['crno'] + 1);


// select data

$sql    = 'SELECT * FROM ComData WHERE com_no = '. $_GET['crno'];
$result = $conn->query($sql);



if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
        $pageTitle = $row['com_eng_name'] . $row['com_chi_name'];

        $com_no = $row['com_no'];   
        $br_no = $row['br_no'];     
        $com_eng_name = $row['com_eng_name'];
        $com_chi_name = $row['com_chi_name'];       
        $com_type = $row['com_type'];   
        $date_of_incorp = $row['date_of_incorp'];   
        $active_status = $row['active_status']; 
        $date_commenced_dormancy = $row['date_commenced_dormancy']; 
        $remarks = $row['remarks'];
        $date_of_dissolution = $row['date_of_dissolution']; 
        $register_charges = $row['register_charges'];       
        $name_history = $row['name_history'];       
        $phone = $row['phone'];     
        $email = $row['email'];     
        $address = $row['address'];     
        $website = $row['website'];     
        $background = $row['background'];           
        $update_time = $row['update_time']; 




    }
} else {
    echo "No Results";
}

$conn->close();
?>

第二个连接:

<?php
header('Content-Type: text/html; charset=utf-8');

$servername = "localhost";
$username = "abcabc";
$password = "12341234";
$dbname = "abc1234";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
$conn->set_charset("utf8");
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 



// select data for similar search

$string = "$com_eng_name";
$words = implode(' ', array_slice(explode(' ', $string ), 0, 2));


$sql = "SELECT * FROM ComData 
        WHERE com_eng_name REGEXP '$words'
        ORDER BY com_no 
        DESC 
        LIMIT 20";
$result = $conn->query($sql);


if ($result->num_rows > 0) {
    echo "<table><tr><th>CR No.</th><th>Company Name</th><th>Active Status</th></tr>";
    // output data of each row
    while($row = $result->fetch_assoc()) {
        echo "<tr><td>".$row["com_no"]."</td><td><a href='search.php?crno=".$row["com_no"]."' >".$row["com_eng_name"]." ".$row["com_chi_name"]."</a></td><td>".$row["active_status"]."</td></tr>";
    }
    echo "</table>";
} else {
    echo "0 results";
}
$conn->close();
?>

Answer 1

如果这两段代码都存在于同一个物理文件中，那么由于在这两种情况下保存连接的变量都是 $conn 你可以放弃第二次尝试建立与数据库。

因此，只需从您称为“第二个连接”的代码段中删除此代码的注释即可，即这一点

$servername = "localhost";
$username = "abcabc";
$password = "12341234";
$dbname = "abc1234";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
$conn->set_charset("utf8");
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

然后删除此行

$conn->close();

来自您调用First Connetion的代码，这样您就不会在第二段代码运行之前关闭连接。

但是，实际上这两段代码位于单独的 .php 文件中。他们必须保持原样。