MYSQL更新選擇 - 升級列

Question

BD WordPress的 - 表：wp_term_relationships

 
object_id | term_taxonomy_id| term_order 
    1  |  23   |   0 
    2  |  22   |   0 
    3  |  23   |   0 
    4  |  22   |   0 
    5  |  23   |   0 
    6  |  21   |   0 

我需要算多少「產品」在每一個「類」屬於在列「term_order」

例如插入：

 
object_id | term_taxonomy_id| term_order 
    1  |  23   |   3 
    2  |  22   |   2 
    3  |  23   |   3 
    4  |  22   |   2 
    5  |  23   |   3 
    6  |  21   |   1 

我做了這樣的事情，但它沒有更新的領域 'term_order'：

UPDATE `letras`.`wp_term_relationships` 
SET `term_order` = '2' 
WHERE `wp_term_relationships`.`object_id` = '5' ; 

SELECT object_id as id_objeto, 
     COUNT( `object_id`) quantidade 
FROM wp_term_relationships 
WHERE `object_id` = `object_id` 
GROUP BY `term_taxonomy_id` 

Answer 1

您可以加入該表本身使用子查詢：

update t 
set term_order = t2.cnt 
from wp_term_relationships t 
    join (
    select term_taxonomy_id, count(*) cnt 
    from wp_term_relationships 
    group by term_taxonomy_id 
) t2 on t.term_taxonomy_id = t2.term_taxonomy_id; 

• SQL Fiddle Demo

---

既然你正在使用MySQL，這應該工作：

update wp_term_relationships 
    join (
    select term_taxonomy_id, count(*) cnt 
    from wp_term_relationships 
    group by term_taxonomy_id 
) t2 on wp_term_relationships.term_taxonomy_id = t2.term_taxonomy_id 
set wp_term_relationships.term_order = t2.cnt; 

• Updated Fiddle

Answer 2

對不起！

我EXCUTE在phpMyAdmin：

 
update t 
set term_order = t2.cnt 
from wp_term_relationships t 
    join (
    select term_taxonomy_id, count(*) cnt 
    from wp_term_relationships 
    group by term_taxonomy_id 
) t2 on t.term_taxonomy_id = t2.term_taxonomy_id; 

錯誤：

1064 - 你在你的SQL語法錯誤;請檢查與您的MySQL服務器版本對應的手冊，以找到正確的語法，以便在第3行使用「from wp_term_relationships t join（select term_taxonomy_id，count（*）cn'