以下是PHP中的基本增删改查代码示例:
增加数据:
<?php // 连接数据库 $conn = mysqli_connect("localhost", "username", "password", "database"); // 检查连接是否成功 if (!$conn) { die("连接失败: " . mysqli_connect_error()); } // 插入数据 $sql = "INSERT INTO users (name, email, password) VALUES ('John Doe', 'johndoe@example.com', 'password123')"; if (mysqli_query($conn, $sql)) { echo "新记录已成功插入"; } else { echo "Error: " . $sql . "<br>" . mysqli_error($conn); } // 关闭连接 mysqli_close($conn); ?>
删除数据:
<?php // 连接数据库 $conn = mysqli_connect("localhost", "username", "password", "database"); // 检查连接是否成功 if (!$conn) { die("连接失败: " . mysqli_connect_error()); } // 删除数据 $sql = "DELETE FROM users WHERE id=1"; if (mysqli_query($conn, $sql)) { echo "记录已成功删除"; } else { echo "Error: " . $sql . "<br>" . mysqli_error($conn); } // 关闭连接 mysqli_close($conn); ?>
更新数据:
<?php // 连接数据库 $conn = mysqli_connect("localhost", "username", "password", "database"); // 检查连接是否成功 if (!$conn) { die("连接失败: " . mysqli_connect_error()); } // 更新数据 $sql = "UPDATE users SET name='Jane Doe', email='janedoe@example.com', password='newpassword123' WHERE id=1"; if (mysqli_query($conn, $sql)) { echo "记录已成功更新"; } else { echo "Error: " . $sql . "<br>" . mysqli_error($conn); } // 关闭连接 mysqli_close($conn); ?>
查询数据:
<?php // 连接数据库 $conn = mysqli_connect("localhost", "username", "password", "database"); // 检查连接是否成功 if (!$conn) { die("连接失败: " . mysqli_connect_error()); } // 查询数据 $sql = "SELECT * FROM users"; $result = mysqli_query($conn, $sql); // 检查查询结果是否为空 if (mysqli_num_rows($result) > 0) { // 输出数据 while ($row = mysqli_fetch_assoc($result)) { echo "id: " . $row["id"] . " - Name: " . $row["name"] . " - Email: " . $row["email"] . "<br>"; } } else { echo "0 结果"; } // 关闭连接 mysqli_close($conn); ?>
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