如何使用PHP表单从多个表中检索数据？

Question

我想使用点运算符/联接从多个表中检索数据，其中参数是从HTML / PHP表单传递的。

HTML代码

<input name="rollno" type="text" placeholder="Roll Number" required>
<input name="submit_view_details" type="submit" value="Proceed">

PHP代码

if(isset($_POST['submit_view_details']))
{
    $rollno = (int) $_POST['rollno'];
    $query = "select * from table1, table2 where table1.{$rollno}=table2.{$rollno}";
    $result=mysqli_query($connection,$query);
}

在浏览器中，如果输入输入1并回显此查询，则如下所示：
select * from table1, table2 where table1.1=table2.1

并且即使表中有数据，也不会获取任何行。

它仅在查询如下所示时有效：
select * from table1,table2 where table1.rollno=table2.rollno

但是，在那种情况下，它获取所有行，但是我只需要用户以上述形式输入的rollno行。

我只是无法解决这个问题。 帮助将不胜感激。 谢谢！

Answer 1

使用AND关键字指定rollno。

SELECT * FROM table1, table2 WHERE table1.rollno = table2.rollno 
AND table1.rollno = {$rollno};

您可能会像这样使用关键字JOIN ：

SELECT * FROM table1 NATURAL JOIN table2 
WHERE rollno = {$rollno};

Answer 2

您需要加入

从这里参考联接，

我相信这会有所帮助

http://www.tutorialspoint.com/mysql/mysql-using-joins.htm

Answer 3

您应该像这样使用join

$query = "SELECT tbl1.*, tbl2.* 
          FROM tbl1 
          INNER JOIN tbl2 ON tbl1.id = tbl2.id 
          WHERE tbl1.column = value ";

Answer 4

foreach ($pieces_2 AS $value) {
         $pieces_3[] ="(CONCAT_WS('|',$presql2) like '%$value%')";      //concat all columns from one table
 }
 $serch_jyouken = implode(" and ",$pieces_3);       // for multiple keywords                    
 $result1 = mysqli_query($connection, "select p.p_no from pfr_data p where (" .$serch_jyouken .")");
 $res1 = array();
 while($r1 = mysqli_fetch_array($result1){
         $res1[] = $r1['p_no'] ;        //fetch primary key from table and store it into array 
 }
 foreach ($pieces_2 AS $value) {            
         $pieces_4[] ="(CONCAT_WS('|',$presql3) like '%$value%')";      // same as above
 }
 $serch_jyouken1 = implode(" and ",$pieces_4);
 $result2 = mysqli_query($connection, "select p2.p_no from pfr_mod_inform p2 where (" .$serch_jyouken1 .")" );
$res2 = array();
 while($r2 = mysqli_fetch_array($result2)){                                                                               
         $res2[] = $r2['p_no'];
 }
 $res_mrg = array_merge($res1 , $res2);     //merge array
 $result = implode("','",$res_mrg );        // array to sring
 $sql5 = $presql ." from pfr_data p where p.p_no in ('$result') order by p.section_p,p.status,p.no";