Php MySQL从另一个表插入随机值
您好,我想将一些随机值从一个表插入到另一个表。我的查询如下所示:Php MySQL从另一个表插入随机值,php,mysql,sql,database,sqlite,Php,Mysql,Sql,Database,Sqlite,您好,我想将一些随机值从一个表插入到另一个表。我的查询如下所示: INSERT INTO `rounds`(`matchID`, `questionOneID`, `questionTwoID`, `questionThreeID`) VALUES (17,(SELECT `id` FROM `questions` ORDER BY RAND() LIMIT 3)) 问题是,mysql需要4个参数(matchID、questionOneID,…),但只得到两个(17,(…)),我如何告诉mys
INSERT INTO `rounds`(`matchID`, `questionOneID`, `questionTwoID`, `questionThreeID`) VALUES (17,(SELECT `id` FROM `questions` ORDER BY RAND() LIMIT 3))
问题是,mysql需要4个参数(matchID、questionOneID,…),但只得到两个(17,(…)),我如何告诉mysql它从SELECT中获得3个参数?
我真的必须:
INSERT INTO `rounds`(`matchID`, `questionOneID`, `questionTwoID`, `questionThreeID`) VALUES (17,(SELECT `id` FROM `questions` ORDER BY RAND() LIMIT 1),(SELECT `id` FROM `questions` ORDER BY RAND() LIMIT 1),(SELECT `id` FROM `questions` ORDER BY RAND() LIMIT 1))
或者有更好的方法吗?您的查询看起来是正确的。我会用
insert。选择
:
INSERT INTO `rounds`(`matchID`, `questionOneID`, `questionTwoID`, `questionThreeID`)
SELECT 17,
(SELECT `id` FROM `questions` ORDER BY RAND() LIMIT 1),
(SELECT `id` FROM `questions` ORDER BY RAND() LIMIT 1),
(SELECT `id` FROM `questions` ORDER BY RAND() LIMIT 1);
如果你想保证这三个问题是不同的,那么我可以选择这种方法:
INSERT INTO `rounds`(`matchID`, `questionOneID`, `questionTwoID`, `questionThreeID`)
SELECT 17,
substring_index(group_concat(id order by rnd), ',', 1),
substring(substring_index(group_concat(id order by rnd), ',', 2), ',', 11),
substring_index(group_concat(id order by rnd), ',', -1),
FROM (SELECT id, rand() as rnd FROM questions ORDER BY RAND() LIMIT 3) q
这将在一行上放置三个随机问题,没有重复项(除非id
在questions
中重复)