空白判定のやり方について

前提・実現したいこと

複数指定して検索できる機能を作りたい
if文でemptyで空文字の箇所を調べてsqlを書いていくしかないのでしょうか？
6つ判定しようとif文を書くと6の階乗個(約750個)のif文を書かなければいけない。
（下記のスクリーンショット参考）

発生している問題・エラーメッセージ

if文以外で対処できないか？

該当のソースコード

php
1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
2<html>
3<head>
4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
5<title>PHP課題</title>
6</head>
7<body>
8<?php
9try
10{
11	$dsn = 'mysql:dbname=personal;host=localhost';
12	$user = 'root';
13	$password = '';
14	$dbh = new PDO($dsn,$user,$password);
15	$dbh->query('SET NAMES utf8');
16
17	$Flag = TRUE;
18
19	$gender=$_POST['gender'];
20	$blood=$_POST['bloodtype'];
21	$kenmei=$_POST['kenmei'];
22	$fromold=$_POST['fromold'];
23	$old=$_POST['old'];
24	$carrier=$_POST['carrier'];
25	$fromcurry=$_POST['fromcurry'];
26	$curry=$_POST['curry'];
27
28	$gender=htmlspecialchars($gender);
29	$blood=htmlspecialchars($blood);
30	$kenmei=htmlspecialchars($kenmei);
31	$fromold=htmlspecialchars($fromold);
32	$old=htmlspecialchars($old);
33	$carrier=htmlspecialchars($carrier);
34	$fromcurry=htmlspecialchars($fromcurry);
35	$curry=htmlspecialchars($curry);
36
37	if(empty($gender)&&empty($blood)&&empty($kenmei)&&(empty($fromold)||empty($old))&&empty($carrier)&&(empty($fromcurry)||empty($curry)))
38	{
39		print '入力されていません';
40		$Flag=FALSE;
41	}
42	else if(!empty($gender))
43	{
44		$sql = 'SELECT info.name, info.furigana, info.address, info.gender, 
45				info.old, info.birthday, info.marriage, info.bloodtype, 
46				kenmei.name AS kenmei, info.phone, info.carrier, info.curry
47				FROM info
48				INNER JOIN kenmei ON info.code = kenmei.id
49				WHERE info.gender = "'.$gender.'"';
50		//'SELECT * FROM info WHERE name = "'.$namae.'"';
51	}
52	else if(!empty($blood))
53	{
54		$sql = 'SELECT info.name, info.furigana, info.address, info.gender, 
55				info.old, info.birthday, info.marriage, info.bloodtype, 
56				kenmei.name AS kenmei, info.phone, info.carrier, info.curry
57				FROM info
58				INNER JOIN kenmei ON info.code = kenmei.id
59				WHERE info.bloodtype = "'.$blood.'"';
60	}
61	else if(!empty($kenmei))
62	{
63		$sql = 'SELECT info.name, info.furigana, info.address, info.gender, 
64				info.old, info.birthday, info.marriage, info.bloodtype, 
65				kenmei.name AS kenmei, info.phone, info.carrier, info.curry
66				FROM info
67				INNER JOIN kenmei ON info.code = kenmei.id
68				WHERE code = "'.$kenmei.'"';
69		//$sql = 'SELECT * FROM info WHERE code = "'.$kenmei.'"';
70	}
71	else if(!empty($fromold)&&!empty($old))
72	{
73		$sql = 'SELECT info.name, info.furigana, info.address, info.gender, 
74				info.old, info.birthday, info.marriage, info.bloodtype, 
75				kenmei.name AS kenmei, info.phone, info.carrier, info.curry
76				FROM info
77				INNER JOIN kenmei ON info.code = kenmei.id
78				WHERE info.old BETWEEN "'.$fromold.'"AND"'.$old.'"';
79	}
80	else if(!empty($carrier))
81	{
82		$sql = 'SELECT info.name, info.furigana, info.address, info.gender, 
83				info.old, info.birthday, info.marriage, info.bloodtype, 
84				kenmei.name AS kenmei, info.phone, info.carrier, info.curry
85				FROM info
86				INNER JOIN kenmei ON info.code = kenmei.id
87				WHERE info.carrier = "'.$carrier.'"';
88	}
89	else if(!empty($fromcurry)&&!empty($curry))
90	{
91		$sql = 'SELECT info.name, info.furigana, info.address, info.gender, 
92				info.old, info.birthday, info.marriage, info.bloodtype, 
93				kenmei.name AS kenmei, info.phone, info.carrier, info.curry
94				FROM info
95				INNER JOIN kenmei ON info.code = kenmei.id
96				WHERE info.curry = "'.$fromcurry.'・'.$curry.'"';
97	}
98	
99	//if(!empty($sql))
100	if($Flag)
101	{
102		$stmt = $dbh->prepare($sql);
103		$stmt->execute();
104
105	$a = 0;
106
107	while(1)
108	{
109		$rec = $stmt->fetch(PDO::FETCH_ASSOC);
110		if($rec==false&&$a==0)
111		{
112			print '検索結果がありません';
113			break;
114		}
115		else if($rec==false&&$a==1)
116		{
117			break;
118		}
119		$a = 1;
120		print	'<table border="1" cellspacing="0" cellpadding="5">';
121   	 	print '<tr>';
122      	print '<th>名前</th>';
123      	print '<th>ふりがな</th>';
124	  	print '<th>メールアドレス</th>';
125	  	print '<th>性別</th>';
126	  	print '<th>年齢</th>';
127	  	print '<th>誕生日</th>';
128	  	print '<th>結婚</th>';
129		print '<th>血液型</th>';
130		print '<th>都道府県</th>';
131		print '<th>電話番号</th>'; 
132		print '<th>キャリア</th>';
133		print '<th>カレーの食べ方</th>';
134
135    	print '</tr>';
136    	print '<tr>';
137      	print '<td>'.$rec['name'].'</td>';
138      	print '<td>'.$rec['furigana'].'</td>';
139      	print '<td>'.$rec['address'].'</td>';
140      	print '<td>'.$rec['gender'].'</td>';
141      	print '<td>'.$rec['old'].'</td>';
142     	print '<td>'.$rec['birthday'].'</td>';
143     	print '<td>'.$rec['marriage'].'</td>';
144     	print '<td>'.$rec['bloodtype'].'</td>';
145      	print '<td>'.$rec['kenmei'].'</td>';
146      	print '<td>'.$rec['phone'].'</td>';
147      	print '<td>'.$rec['carrier'].'</td>';
148	  	print '<td>'.$rec['curry'].'</td>';
149    	print '</tr>';
150  	 	print '</table>';
151	}
152
153	$dbh = null;
154}
155}
156catch(Exception $e)
157{
158	print $e;
159}
160	print '</br>';
161	print'<input type="button" onclick="history.back()" value="戻る">';
162
163?>
164
165</body>
166</html>