帮助加入并加入群组

Question

必须有一种方法才能使用1个查询。我使用的是加入和一组由

这里是我当前的代码假设：

$sql = mysql_query("select * from `databases` where `id` in (select `id_database` from `categories`)"); 

while ($row = mysql_fetch_assoc($sql)) 
{ 
    echo $row['name'] . '<br />'; 

    $sql_c = mysql_query("select * from `categories` where `id_database`='" . $row['id'] . "'"); 

    while ($row_c = mysql_fetch_assoc($sql_c)) 
    { 
     echo $row_c['title'] . '<br />'; 
    } 
} 

Answer 1

有......这样的事情应该做的伎俩。

$sql = mysql_query("select * from databases db JOIN categories cat on (db.id=cat.id_database) ORDER BY db.name"); 

$last_name = null; 
while ($row = mysql_fetch_assoc($sql)) 
{ 
    if($row['db.name'] !== $previous_name) { 
     echo $row['db.name'] . '<br />'; 
     $previous_name = $row['db.name']; 
    } 
    echo $row['cat.title'] . '<br />'; 
} 

Answer 2

select d.name, c.title from databases as d, categories as c where d.id=c.id_database;