mysql - MySQL 的 SQL 查询

Question

我有 2 张桌子：

Table:skill
SkillID int(10) unsigned
Description varchar(100)

Table: question
QuestionID int(10) unsigned
SkillID int(10) unsigned
Details varchar(100)

每个技能的问题表中有很多行。我想运行一个查询，列出所有技能，并且该技能只有一个问题（不管哪个问题）。

怎么可能呢？

Answer 1

FOR MYSQL 和 SQLSERVER

SELECT * 
FROM skill S 
INNER JOIN question Q ON S.SkillID=Q.SkillID 
INNER JOIN (
SELECT SkillID ,max(QuestionID) QuestionID
FROM question
GROUP BY SkillID)T
ON S.SkillID =T.SkillID AND Q.QuestionID=T.QuestionID

为MYSQL

SELECT SkillID ,max(QuestionID) QuestionID
FROM question
GROUP BY SkillID

Answer 2

你可以试试这个：

SELECT SkillID, QuestionID -- or, whatever fields you would need
FROM question
GROUP BY SkillID
ORDER BY RAND()