Question

坚持这个...
我需要类似GROUP BY的东西，但也会影响列cat_name中所有其他行的分组结果，相应于id（示例中为prod_id）。示例表：

 +------------------+--------+---------+-------------+--------------+
 | cat_name         | cat_id | prod_id | prod_name   | prod_img     |
 +------------------+--------+---------+-------------+--------------
 | Foo Category     |     54 |     755 | product a   | prod_a_img_1 |
 | A Category       |     22 |     755 | product a   | prod_a_img_3 |
 | Bar Category     |     59 |     755 | product a   | prod_a_img_2 |
 | Category three   |     85 |     767 | product b   | prod_b_img_1 |
 +------------------+--------+---------+-------------+--------------+

我想要的是：

+------------------+--------+---------+-------------+--------------+
| cat_name         | cat_id | prod_id | prod_name   | prod_img     |
+------------------+--------+---------+-------------+--------------
| A Category       |     54 |     755 | product a   | prod_a_img_1 |
| A Category       |     22 |     755 | product a   | prod_a_img_3 |
| A Category       |     59 |     755 | product a   | prod_a_img_2 |
| Category three   |     85 |     767 | product b   | prod_b_img_1 |
+------------------+--------+---------+-------------+--------------+

类别具有唯一ID，但我需要在每行中仅选择第一个类别（按字母顺序排列）。

我的完整查询：

select categories.name as cat_name,
   categories.slug as cat_uri,
   categories.term_id as cat_id,
   object_id,
   term_taxonomy_id,
   ID as prod_id,
   post_title as prod_name,
   img as prod_img
   from
   wp_posts,
   wp_term_relationships,
   (select term_id,
   name,
   slug
   from
   wp_terms group by name) as categories
   where post_type = "product" and
   object_id = ID and
   term_taxonomy_id = term_id

Answer 1

我认为你看起来像这样：

SELECT (
        SELECT ti.cat_name 
        FROM yourTable ti 
        WHERE ti.prod_id = t.prod_id
        ORDER BY ti.cat_name
        LIMIT 1) As cat_name, 
    t.cat_id, 
    t.prod_id, 
    t.prod_name, 
    t.prod_img
FROM 
    yourTable t

按字母顺序分组基于ID的所有行

1 个答案: