php - 比较 MYSQL 中的两个表

Question

我必须比较两个表，然后将它们全部列为复选框，而匹配的值应该被选中，不匹配的值则不被选中

//表1

rid| role_name  
1  |    school  
2  |    college  
3  |  University  

//表2

id|rid | category  
1 | 1  |  uniform  
2 | 2  |  uniform

从两个表中匹配去掉，其中类别 = 'uniform' 列出所有并检查匹配的rid

Answer 1

    $query = "select t1.rid, 'matched' as matching from table1 t1 where t1.rid  in (
              select rid from table2 where category = 'uniform')
             union
             select t1.rid ,'notmatched' from table1 t1 where t1.rid not in (
             select rid from table2 where category = 'uniform')";
    $result = mysqli->query($query);
    $fetched = $result->fetch_assoc();
    foreach($fetched as $row){
    if($row['matching'] = 'matched'){
           echo "<input type='checkbox' name='{$row['rid']}' value='' checked='checked' >"; }
    else{ 
            echo "<input type='checkbox' name='{$row['rid']}' value=''  >"; }
     }

SQL DEMO