php - 带有两个 SELECT 语句的 INSERT

Question

这是我目前正在尝试的，但我收到了一个 mySQL 错误：

mysql_query ("INSERT INTO profile_tag (profile_id, tag_id) 
(SELECT profile_id FROM profile WHERE username = '$username'), 
(SELECT tag_id FROM  tag WHERE  tag = '$music' OR tag = '$sports' OR tag = '$tech')"); 

但是，我可以INSERT使用单个SELECT语句完成一个，而不是两个。

我收到的错误：

查询无效：您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，以'(SELECT tag_id FROM tag WHERE tag = '' OR tag = 'sports' OR tag = '')'在第 1 行附近使用正确的语法

Answer 1

Much like the error says, the syntax is incorrect. The values of the insert has to match the number of values in the column definition.

INSERT INTO profile_tag (profile_id, tag_id)
SELECT
    profile_id, tag_id
FROM
    profile
    CROSS JOIN tag
WHERE
    username = ?
    AND tag IN (?, ?, ?)

Note that this will insert multiple rows if a tag value is found for each of the inputs, but I believe that is what you want.

Answer 2

You can use VALUES clause

insert into profile_tag(user_id, tag_id) values
((select id from users where username = 'alice'),
 (select id from tags where tag = 'music'));

http://sqlfiddle.com/#!2/76439/1/0

Answer 3

mysql_query ("INSERT INTO profile_tag (profile_id, tag_id) 
(SELECT profile.profile_id, tag.tag_id FROM profile LEFT JOIN tag ON 1 WHERE profile.username = '$username' AND tag.tag IN ('$music', '$sports', '$tech'))");