Question

请告诉我有关解决此问题的任何想法。

我有两张桌子

类：

id .... category .... parent

1 .... general .... 0

2 ....新闻...... 0

消息： id ....标题.... category_id

1 .... headline1 .... 1

2 .... headline2 .... 2

3 .... headline3 .... 2

4 .... headline4 .... 1

我有这个MYSQL

代码：

SELECT * FROM news INNER JOIN categories ON news.category_id=categories.id group by category_id,date

现在我想根据类别

获取行

所以我得到这样的结果：

一般类别：

headline1

headline4

新闻类别：

headline2

headline3

请帮助我这些家伙

Answer 1

$getcategories = mysql_query("SELECT DISTINCT id FROM categories");
$categories = mysql_num_rows($getcategories);

if($categories > 0){
    echo "<table width='100%' cellspacing='0' cellpadding='0'>";

    while ($rowcategories = mysql_fetch_assoc($getcategories)) {

    $category_id = $rowcategories['id'];
    $category_title = $rowcategories['category'];

    $getnews = mysql_query("SELECT * FROM news WHERE category_id = '$category_id'");
    $news = mysql_num_rows($getnews);


        if($news > 0){
        echo "<tr><td>$category_title</td></tr>";

            while ($rownews = mysql_fetch_assoc($getnews)) {

            $news_headline = $rownews['headline'];
            // all other info you want to pull here

            echo "<tr><td>ROW WITH NEWS INFO HERE</td></tr>";

            } // end news loop
        } // end if news > 0
    echo "</table>";
    } // end if categories > 0
} // end categories loop

Answer 2

You dont need group by. You need **order by**.

查看我的mysql日志。

mysql> create table categories ( id int , category varchar(20), parent int);
Query OK, 0 rows affected (0.06 sec)

mysql> create table headlines ( id int, headline varchar(30), category_id int);
Query OK, 0 rows affected (0.05 sec)

mysql> insert into categories values (1, 'general', 0) , (2, 'news', 0);
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> insert into headlines values (1, 'headline1', 1), (2, 'headline2', 2), (3, 'headline3', 2), (4, 'headline4', 1);
Query OK, 4 rows affected (0.00 sec)
Records: 4  Duplicates: 0  Warnings: 0


mysql> select category ,  headline from headlines as h join categories as c on (c.id = h.category_id)  order by category, headline ;
+----------+-----------+
| category | headline  |
+----------+-----------+
| general  | headline1 |
| general  | headline4 |
| news     | headline2 |
| news     | headline3 |
+----------+-----------+
4 rows in set (0.00 sec)

如何根据类别获取多个记录

2 个答案: