Question

我有这个sql语句连接3个表：

SELECT * FROM `int_news` 
                       LEFT JOIN tl_member ON int_news.member_id = tl_member.id
                       LEFT JOIN tl_news ON int_news.news_id = tl_news.id

3个表格如下：

表1（int_news） ID，member_id，news_id

表2（tl_member） id，firstname，lastname

表3（tl_news） id，标题

到目前为止一切都那么好，但似乎我头脑中有一个黑洞让我无法解决如何输出这样的结果

对于每个“标题”，我想要所有的姓氏，例如

headline 1       Jonny
                 Walker
                 Jim

headline 2       Knopf
                 Jon
                 Doe

Answer 1

听起来你看起来像一个支点，所以如果按标题对查询进行分组，它会将每个姓氏显示为一列。

我找到了关于mysql的枢轴的这个很好的教程，它可以帮助你http://www.artfulsoftware.com/infotree/queries.php#78

headline 1       Jonny    Walker    Jim

headline 2       Knopf    Jon       Doe

这是一个可以做到这一点的循环*原谅我的php已经有一段时间了。

$curHeadline = "";

while ( $db_field = mysql_fetch_assoc($result) ) {

    if($curHeadline != $db_field['headline'])
    {
        $curHeadline = $db_field['headline'];
        print $curHeadline . $db_field['ID']
    }

    print $db_field['lastName'] . "<BR>";
}

Answer 2

这样的事情会模糊地反映出你的情况吗？

<?php

$sql = "
    SELECT
        `int_news`.`ID` AS `int_news_ID`, 
        `int_news`.`member_id`, 
        `int_news`.`news_id`, 
        `t1_member`.`id` AS `t1_member_id`, 
        `t1_member`.`firstname`,
        `t1_member`.`lastname`,      /* desired */
        `t1_news`.`id` AS `t1_news_id`, 
        `t1_news`.`headline`         /* desired */
    FROM
        `int_news` 
    LEFT JOIN `tl_member` ON `int_news`.`member_id` = `tl_member`.`id`
    LEFT JOIN `tl_news` ON `int_news`.`news_id` = `tl_news`.`id`
";

$res = mysql_query($query);

$arrHeadings = array();
while($row = mysql_fetch_assoc($res)) {
 // We want to output the results in groups of headings
 $arrHeadings[$row['heading']][] = $row;
}

// Don't forget to cleanse for html output (unlike below)
// Loop through the headers
foreach($arrHeadings as $heading=>$arrRow) {
 echo '<dl>';
 echo '<dt>'.$heading.'</dt>';
 echo '<dd>';

 // Loop through rows with the same header
 foreach($arrRow as $index=>$dbRow) {
  echo $dbRow['lastname'].'<br />';
 }

 echo '</dd>';
 echo '</dl>';
}

?>

Answer 3

尝试使用mysql：

SELECT tlnews.headline, GROUP_CONCAT(tl_member.last_name)
FROM `int_news`  LEFT JOIN tl_member ON int_news.member_id = tl_member.id
                 LEFT JOIN tl_news   ON int_news.news_id   = tl_news.id
GROUP BY 1;

Expected Output:

headline1  Johnny,Walker,Jim
headline2  Knopf,Jon,Doe
...

加入3个表 - 如何查看结果？

3 个答案: