我正在根据标题进行高级搜索，这是我的代码。首先，我是根据整个标题进行搜索。如果没有找到任何一本书，我会根据书名中的每个单词进行搜索。
问题是，如果第二种情况下有两个或多个单词与标题匹配，那么它就会打印重复的书。
$qry="select * from books where quantity>0 ";
if(isset($title)&&isset($submit1))
$qry.=" and title like '%".$title."%' ";
$books=mysqli_query($con,$qry);
$numrows=mysqli_num_rows($books);
if($numrows>0){
while($row=mysqli_fetch_assoc($books)){
//print books
}
}
else if(isset($submit1)&&isset($title)){
$words=explode(" ",$title);
$notfound=true;
foreach($words as $value){
$qry="select * from books where quantity>0 ";
$qry.=" and title like '%".$value."%' ";
$books=mysqli_query($con,$qry);
$numrows=mysqli_num_rows($books);
if($numrows>0){
while($row=mysqli_fetch_assoc($books)){
// print based on each word
}}
您应该更改SQL查询，使用or一次搜索任何单词，而不是对每个单词进行单独的查询，然后处理重复的单词。只是不要忘记括号，因为你有另一个条件。
最终你应该会得到这样的东西：
$words=explode(" ",$title);
$conditions = [];
foreach ($words as $word) {
$conditions[] = "title like '%" . $word ."%'";
}
$query = sprintf(
"select * from books where quantity > 0 and (%s)",
join(" or ", $conditions)
);
$books = mysqli_query($con, $query);
$numrows = $mysqli_num_rows($books);
...