Question

在这个查询中我想更新那些最新发布的记录。但是我的这个查询不起作用请帮帮我是什么原因???

错误： - 您无法在FROM子句

中指定目标表'beevers_products'以进行更新

update beevers_products set product_name='my_product_name' where posted_date in (SELECT posted_date FROM `beevers_products` order by posted_date asc limit 1)

Answer 1

检查一下：

UPDATE beevers_products 
SET product_name = 'my_product_name' 
WHERE posted_date = (SELECT posted_date 
                     FROM beevers_products
                     ORDER BY posted_date DESC limit 1)

Answer 2

建议您使用CI Active Record类进行查询。

http://ellislab.com/codeigniter/user-guide/database/active_record.html

Answer 3

试试这个：

update beevers_products as t1, 
(select posted_date from beevers_products order by posted_date asc limit 1) as t2
set t1.product_name = 'my_product_name'
where t1.posted_date in (t2.posted_date);

您必须为所需的记录提供别名，并在where子句中使用它。

Answer 4

试试这个

UPDATE beevers_products 
SET product_name = 'my_product_name'  
OUTPUT DELETED.product_name
WHERE posted_date in (SELECT posted_date 
                      FROM `beevers_products` 
                      order by posted_date asc 
                      limit 1)

详细了解output

选中此项 - ＆gt; Can I update/select from a table in one query?
可能对你有所帮助

Answer 5

INSERT INTO beevers_products (id, product_name)
SELECT id, 'my_product_name'
FROM beevers_products
ORDER BY posted_date ASC
LIMIT 1
ON DUPLICATE KEY UPDATE product_name = VALUES(product_name)

一旦我学会了INSERT ... SELECT ... ON DUPLICATE这么多可能性浮出水面。只要你想要posted_data ASC或posted_data DESC，我就会有点好奇。

为什么更新和选择两者不能使用相同的表

5 个答案: