我在$Submit==""的SQL"SELECT * FROM MenuData"能正常顯示出來
但把SQL加上WHERE之後"SELECT * FROM MenuData WHERE MD_Classification='$Submit' ORDER BY MD_index ASC"就無法正常顯示
在phpmyadmin 執行條件式的SQL也能正常顯示
找了很久不知道哪裡出了錯

<div class="aaa"><h1>MENU</h1>
	 <form>
	 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
	 <input type="Submit" value="義大利麵" name="Submit" style='width:55px;height:25px;font-size:15px;'>
	 <input type="Submit" value="焗烤麵" name="Submit" style='width:55px;height:25px;font-size:15px;'>
	 <input type="Submit" value="焗烤飯" name="Submit" style='width:55px;height:25px;font-size:15px;'>
	 <input type="Submit" value="蛋包飯" name="Submit" style='width:55px;height:25px;font-size:15px;'>
	 <input type="Submit" value="燴飯" name="Submit" style='width:55px;height:25px;font-size:15px;'>
	 <input type="Submit" value="燉飯" name="Submit" style='width:55px;height:25px;font-size:15px;'><br><br>
	 </form></div>
<div class="qqq"><table border="0">
<tr><td align="right"><h2>單位：新台幣元</h2></td></tr>
</table></div>
<div id="test" class="aaa">
<?php
require_once("mysql_data.php");
mysql_query('set names `utf8`');
session_start();
$sql="SELECT * FROM ShopData WHERE SD_Account='".$_SESSION["SD_Account"]."'";
$record=mysql_query($sql);
$row=mysql_fetch_assoc($record);
$SD_Number=$row["SD_Number"];
//echo $SD_Number;
?>
<?php
	$Submit =!empty($_GET["Submit"]) ? $_GET["Submit"] : null;
	$db = 'CRM';
	mysql_connect('', '', '');
	mysql_select_db("CRM");
	mysql_query("SET CHARACTER SET utf8;");
if($Submit=="")
{
		echo '
				<table border="1" width="1000" align="center">
				<thead>
					<tr>
					<th>餐點編號</th>
					<th>餐點分類</th>
					<th>餐點名稱</th>
					<th>餐點成本</th>
					<th>餐點價格</th>
				</tr></thead>';
		$sql = "SELECT * FROM MenuData";
		$result = mysql_query($sql);
		$num = mysql_num_rows($result);
		for ( $i=1; $i<=$num; $i++ )
		{
			$row = mysql_fetch_row($result);
			$MD_index = $row[0];
			$MD_Classification = $row[2];
			$MD_MealName = $row[3];
			$MD_Cost= $row[4];
			$MD_Price = $row[5];
			echo "<tr>";
			echo "<td>$i</td>";
			echo "<td>$MD_Classification</td>";
			echo "<td>$MD_MealName</td>";
			echo "<td>$MD_Cost</td>";
			echo "<td>$MD_Price</td>";
		}
		echo   '</tr></table></div>';
}
else if($Submit!='')
{
		echo $Submit;
		echo '
				<table border="1" width="1000" align="center">
				<thead>
					<tr>
					<th>餐點編號</th>
					<th>餐點分類</th>
					<th>餐點名稱</th>
					<th>餐點成本</th>
					<th>餐點價格</th>
				</tr></thead>';
		$sql = "SELECT * FROM MenuData WHERE MD_Classification='$Submit' ORDER BY MD_index ASC";
		$result = mysql_query($sql) or die('SQL執行錯誤');
		$num = mysql_num_rows($result);
		for ( $i=1; $i<=$num; $i++ )
		{
			$row = mysql_fetch_row($result);
			$MD_Classification = $row[2];
			$MD_MealName = $row[3];
			$MD_Cost= $row[4];
			$MD_Price = $row[5];
			echo "<tr>";
			echo "<td>$i</td>";
			echo "<td>$MD_Classification</td>";
			echo "<td>$MD_MealName</td>";
			echo "<td>$MD_Cost</td>";
			echo "<td>$MD_Price</td>";
		}
		echo   '</tr></table></div>';	
}
else
{
		echo '錯誤';
}
	mysql_close();
?>