java - sql查询-使用AND

Question

下面的查询没有返回任何结果

SELECT user_id FROM test WHERE  poll_id = 2 AND (question_id = 2 AND answer_id = 5) AND (question_id = 3 AND answer_id = 8);

这是不是正确的语法？

表格数据为

|poll_id | question_id | answer_id | user_id |
|--------|-------------|-----------|---------|
| 2      |   2         |  5        |  2      |  
| 2      |   3         |  8        |  2      |  

结果应该是2

Answer 1

不是因为你where子句中的AND条件不匹配

你应该把它改成:

SELECT user_id FROM test WHERE  poll_id = 2 
AND 
((question_id = 2 AND answer_id = 5) 
OR (question_id = 3 AND answer_id = 8));

更新

SELECT t.user_id FROM test t WHERE  poll_id = 2 
AND exists (   select 1 from test where 
(question_id = 2 AND answer_id = 5 and user_id=t.user_id ))
AND question_id = 3 AND answer_id = 8