PHP MySQL有两个查询

问题描述：

I need to do a SELECT * FROM table_X , the problem is table_X is the result of another query, I don't know how to do it, perhaps with two loop, something like this :

<?php

$query1 = mysql_query("SELECT * FROM table_ref");
while ($row = mysql_fetch_array($query1))
{

     $name = $row['table_name'];

     $query2 = mysql_query(" SELECT * FROM '$name' ");

     while ($row = mysql_fetch_array($query2)) 
     {
         $time = $data['itime'];
         echo $time;      
     }
}

?>

The tables are all similar & I can't do joint there's no keys. So what I want is to show only the results of the second query from each results of the first query !

我需要做一个SELECT * FROM table_X code>，问题是table_X是结果另一个查询，我不知道怎么做，也许有两个循环，如下所示： p>

 ＆lt;？php 
 
 $ query1 = mysql_query（  “SELECT * FROM table_ref”）; 
while（$ row = mysql_fetch_array（$ query1））
 {
 
 $ name = $ row ['table_name']; 
 
 $ query2 = mysql_query（“SELECT *  FROM'$ name'“）; 
 
 while（$ row = mysql_fetch_array（$ query2））
 {
 $ time = $ data ['itime']; 
 echo $ time;  
} 
} 
 
？＆gt; 
  code>  pre> 
 
 这些表格类似于＆amp; 我不能联合那里没有钥匙。 所以我想要的是只显示第一个查询的每个结果中第二个查询的结果！ p> 
  div>

答

So, what's your structure? I don't understand. You have column table_name where are listed a lot of tables? If so, just use backquotes on your $name:

$query2 = mysql_query(" SELECT * FROM `$name` ");

答

just change your quotes to have the query ready to be started

change

 $query2 = mysql_query(" SELECT * FROM '$name' ");

 $query2 = mysql_query(" SELECT * FROM `".$name."` ");

i would also rather sugest to check this part

 while ($row = mysql_fetch_array($query2)) 
 {
     $time = $data['itime'];
     echo $time;      
 }

you already used variable $row to fetching previus query so better to change to something else, look like $data is matching your needs because you already used but you did not declare it

 while ($data = mysql_fetch_array($query2)) 
 {
     $time = $data['itime'];
     echo $time;      
 }

答

Apart from the obvious that has been pointed out in the comments, you're overwriting $row in the second loop.

Also, you're trying to read an array ($data) that is not defined.

The following will work much better (but still isn't ideal):

$query1 = mysql_query("SELECT `table_name` FROM `table_ref`");
while ($row = mysql_fetch_array($query1))
{
     $name = $row['table_name'];
     $query2 = mysql_query("SELECT `itime` FROM `$name`");

     while ($data = mysql_fetch_array($query2)) 
     {
         $time = $data['itime'];
         echo $time;      
     }
}

答

Try this query:

select x.* from ( SELECT table_name FROM table_ref) as x

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