避免检索重复项（MYSQLi / PHP）

Question

如下图所示，其中有一个子类别，其中包含重复项目，原因如下：

它查看课程标题并查看与其关联的子类别并填充该标题。问题在于，如果您有10个课程名称相似并且具有相同子类别的课程，则该子类别将多次显示。因此，我想做的是：

有一个if语句，规定子类别名称已经填充，而不需要再次填充它。以下是如何生成子类别：

          $search_query = $_GET['user_query'];

$get_cats = "select * from courses where (course_title like '%$search_query%' )  AND course_date1 >= CURRENT_DATE() LIMIT 5";

    $run_cats = mysqli_query($con, $get_cats);

    while ($row_cats=mysqli_fetch_array($run_cats)){
        $crs_sub1 = $row_cats['course_subc1'];
                $crs_sub2 = $row_cats['course_subc2'];
                        $crs_sub3 = $row_cats['course_subc3'];

        $crs_sub4 = $row_cats['course_subc4'];

        $crs_sub5 = $row_cats['course_subc5'];




        echo "<a href='searchPage.php?user_query=$crs_sub1' id='liSpacing'><label id='labelSearch'><input type='checkbox' name='checkbox' value='value'>&nbsp;$crs_sub1</label></a> <br />";



    }

提前致谢

更新

原件：

 $get_cats = "select * from courses where (course_title like '%$search_query%' )  AND course_date1 >= CURRENT_DATE() LIMIT 5";

更新：

  $get_cats = "select distinct course_title from courses where (course_title like '%$search_query%' )  AND course_date1 >= CURRENT_DATE() LIMIT 5";

更新后，我收到以下错误：

Notice: Undefined index: course_subc1 in 

Notice: Undefined index: course_subc2 in 

Notice: Undefined index: course_subc3 in 

Notice: Undefined index: course_subc4 in 

Notice: Undefined index: course_subc5 in 


Notice: Undefined index: course_subc1 in

Notice: Undefined index: course_subc2 in 

Notice: Undefined index: course_subc3 in 

Notice: Undefined index: course_subc4 in 
Notice: Undefined index: course_subc5 in 


Notice: Undefined index: course_subc1 in 

Notice: Undefined index: course_subc2 in 

Notice: Undefined index: course_subc3 in 

Notice: Undefined index: course_subc4 in 

Notice: Undefined index: course_subc5 in 

Notice: Undefined index: course_subc1 in 

Notice: Undefined index: course_subc2 in 
Notice: Undefined index: course_subc3 in 
Notice: Undefined index: course_subc4 in 
Notice: Undefined index: course_subc5 in 
Notice: Undefined index: course_subc1 in 
Notice: Undefined index: course_subc2 in 
Notice: Undefined index: course_subc3 in
Notice: Undefined index: course_subc4 in 
Notice: Undefined index: course_subc5 in 

以下是错误行：

 $run_cats = mysqli_query($con, $get_cats);

            while ($row_cats=mysqli_fetch_array($run_cats)){
                $crs_sub1 = $row_cats['course_subc1'];
                        $crs_sub2 = $row_cats['course_subc2'];
                                $crs_sub3 = $row_cats['course_subc3'];

                $crs_sub4 = $row_cats['course_subc4'];

                $crs_sub5 = $row_cats['course_subc5'];

Answer 1

我不确切知道您的桌面结构是什么，但我们会说该字段的名称是＆＃39; course_title＆＃39;

$sql = "select distinct course_title from courses where (course_title like '%$search_query%' )  AND course_date1 >= CURRENT_DATE() LIMIT 5";

Answer 2

首先要做的事情。

要修复查询（并防止未定义的索引错误），您需要执行以下操作：

$get_cats = "select distinct course_title, course_subc1, course_subc2,
course_subc3, course_subc4, course_subc5 from courses where 
(course_title like '%$search_query%' )  AND course_date1 >= CURRENT_DATE()
LIMIT 5";

大但

您正在请求4个不使用的字段：course_subc2，course_subc3，course_subc4和course_subc5。此外，如果这些是类别（他们走路和说话类别）你有一个很大的规范化问题。你应该有一个类别表，并在课程和类别之间建立适当的关系。

Answer 3

您需要SELECT DISTINCT来停止复制。无法编写修订后的查询，因为您没有提供有关表结构的任何信息。学习提供问题所需的数据，您将获得更好的答案。