PHP PDO MS SQL Server 选择限制答案

【问题标题】：PHP PDO MS SQL Server SELECT LIMITPHP PDO MS SQL Server 选择限制
【发布时间】：2020-05-06 16:06:35
【问题描述】：

我正在使用 PHP PDO 将我的项目从基于 MySQL 的 MS SQL 转换为 MS SQL，下面的代码允许线程思想记录（左和右）如果记录可以说 #1 那么它应该保持在 #1 与最后一个相同记录。我得到错误：

注意：试图访问 bool 类型值的数组偏移量 C:\inetpub\wwwroot\dxbase\DB_Project\private\supplierschoice.php 上第 96 行

第 96 行是：

<?php echo "<input type='text' id='CSupplierCode' value='" . $row['SupplierCode'] . "'>"; ?>

在那之前我也有$row = $result->fetch();。

在“左”按钮上运行的代码：

<?php
$sql = "SELECT s.SupplierID, ..., l.StreetAddress, ... FROM Suppliers s LEFT JOIN Locations l ON s.SupplierID = l.RefID WHERE l.LocGroup = 1 AND s.SupplierID < '" . $tID . "' ORDER BY s.SupplierID DESC LIMIT 1";
$result = $conn->prepare($sql);
$result->execute();
if (!$result) {
   $sql = "SELECT s.SupplierID, ..., l.StreetAddress, ... FROM Suppliers s LEFT JOIN Locations l ON s.SupplierID = l.RefID WHERE l.LocGroup = 1 AND s.SupplierID = '" . $tID . "'";
   $result = $conn->query($sql);
   if (!$result) { echo "Error creating a record: " . $sql . "<br>" . $conn -> errorInfo();}
}
?>

代码没有到达第二部分 (!$result)，因此它会给出警告和空输入。

更新：尝试使用 SELECT TOP 1

$sql = "SELECT TOP 1 s.SupplierID, s.SupplierCompany, s.SupplierCode, s.Currency, s.PaymentTerm, s.ShippingTerm, s.TMode, s.Agent, s.Carrier, s.Warehouse, l.StreetAddress, l.Suite, l.City, l.Locality, l.State, l.PostalCode, l.Country FROM Suppliers s LEFT JOIN Locations l ON s.SupplierID = l.RefID WHERE l.LocGroup = 1 AND s.SupplierID < '" . $tID . "' ORDER BY s.SupplierID DESC";
    $result = $conn->query($sql);
    if (!$result) {
        $sql = "SELECT s.SupplierID, s.SupplierCompany, s.SupplierCode, s.Currency, s.PaymentTerm, s.ShippingTerm, s.TMode, s.Agent, s.Carrier, s.Warehouse, l.StreetAddress, l.Suite, l.City, l.Locality, l.State, l.PostalCode, l.Country FROM Suppliers s LEFT JOIN Locations l ON s.SupplierID = l.RefID WHERE l.LocGroup = 1 AND s.SupplierID = '" . $tID . "'";
        $result = $conn->query($sql);
        if (!$result) { echo "Error creating a record: " . $sql . "<br>" . $conn -> errorInfo();}
    }

在 ID 小于 #1 之后它仍然没有到达第二部分，而且似乎 (!$result) 在这里不起作用..

【问题讨论】：

SQL Server 没有LIMIT 关键字，所以你的说法是错误的。
顺便说一句，您仍然对 SQL 注入持开放态度。没有占位符的准备/执行并不能使它成为真正的准备好的语句。
感谢 Funk 四十九的建议，稍后会跟进，只需要确保我所拥有的工作正常
@MaxCB 使用SELECT TOP (1) ... 而不是LIMIT 1。
这里的 $result 似乎总是 TRUE，即使小于 #1 的 ID 不存在

标签： php sql-server pdo

【解决方案1】：

好的！经过 100 次试验和错误后，我得到以下代码正常工作用于在 MS SQL Server 中左右移动

} elseif ($tID > 0 && $Order == 3) {
    $sql = "SELECT TOP 1 s.SupplierID, s.SupplierCompany, s.SupplierCode, s.Currency, s.PaymentTerm, s.ShippingTerm, s.TMode, s.Agent, s.Carrier, s.Warehouse, l.StreetAddress, l.Suite, l.City, l.Locality, l.State, l.PostalCode, l.Country FROM Suppliers s LEFT JOIN Locations l ON s.SupplierID = l.RefID WHERE l.LocGroup = 1 AND s.SupplierID < '" . $tID . "' ORDER BY s.SupplierID DESC";
    $result = $conn->query($sql);
    $row = $result->fetch(PDO::FETCH_ASSOC);
    if (!$row) {
        $sql = "SELECT s.SupplierID, s.SupplierCompany, s.SupplierCode, s.Currency, s.PaymentTerm, s.ShippingTerm, s.TMode, s.Agent, s.Carrier, s.Warehouse, l.StreetAddress, l.Suite, l.City, l.Locality, l.State, l.PostalCode, l.Country FROM Suppliers s LEFT JOIN Locations l ON s.SupplierID = l.RefID WHERE l.LocGroup = 1 AND s.SupplierID = '" . $tID . "'";
        $result = $conn->query($sql);
        $row = $result->fetch(PDO::FETCH_ASSOC);
    }
} elseif ($tID > 0 && $Order == 7) {
    $sql = "SELECT TOP 1 s.SupplierID, s.SupplierCompany, s.SupplierCode, s.Currency, s.PaymentTerm, s.ShippingTerm, s.TMode, s.Agent, s.Carrier, s.Warehouse, l.StreetAddress, l.Suite, l.City, l.Locality, l.State, l.PostalCode, l.Country FROM Suppliers s LEFT JOIN Locations l ON s.SupplierID = l.RefID WHERE l.LocGroup = 1 AND s.SupplierID > '" . $tID . "' ORDER BY s.SupplierID ASC";
    $result = $conn->query($sql);
    $row = $result->fetch(PDO::FETCH_ASSOC);
    if (!$row) {
        $sql = "SELECT s.SupplierID, s.SupplierCompany, s.SupplierCode, s.Currency, s.PaymentTerm, s.ShippingTerm, s.TMode, s.Agent, s.Carrier, s.Warehouse, l.StreetAddress, l.Suite, l.City, l.Locality, l.State, l.PostalCode, l.Country FROM Suppliers s LEFT JOIN Locations l ON s.SupplierID = l.RefID WHERE l.LocGroup = 1 AND s.SupplierID = '" . $tID . "'";
        $result = $conn->query($sql);
        $row = $result->fetch(PDO::FETCH_ASSOC);
    }

【讨论】：