Mysql 选择子查询中除结果之外的所有结果

我有一个连接多个表（3或4）的查询，并按预期获得结果

SELECT DISTINCT test_title, stt_id FROM student_tests
LEFT JOIN student_test_answers ON sta_stt_num = stt_id 
JOIN tests ON stt_test_id = test_id
WHERE student_test_answer_id IS NULL 

我还有一个查询，显示了另一组数据，基本上是这样的：

    SELECT test_id, COUNT(*) AS theCount FROM tests
    JOIN test_questions ON test_id= tq_test_id
    WHERE type= 'THE_TYPE'
    GROUP BY test_id
    HAVING theCount = 1

所以基本上我不想在第一个查询中包含第二个查询的结果。测试id将是连接字段

我尝试了一个WHERE NOT EXISTS（-上述查询-），但没有返回不正确的结果。我也试过‘不在（）’

---

有更好的方法吗？

试试这样的方法：

(SELECT test_id, COUNT(*) AS theCount FROM tests
JOIN test_questions ON test_id= tq_test_id
WHERE type= 'THE_TYPE'
GROUP BY test_id
HAVING theCount = 1) outer
LEFT JOIN (
      [OtherQuery]
) a ON outer.test_id = a.test_id 
WHERE a.test_id IS NULL

select     test.test_id, count(*) as theCount
from       tests test
join       test_questions tq
on         tq.test_id = test.test_id
left join  tests excluded_test
on         excluded_test.test_id = test.test_id
where      tq.type = 'THE_TYPE'
and        << Some condition that explains what excluded_test is >>
and        excluded_test.test_id is null

SELECT
   DISTINCT test_title,
   olc_stt_i_num 
FROM
   student_tests  
LEFT JOIN
   student_test_answers 
      ON olc_sta_i_stt_num = olc_stt_i_num   
INNER JOIN
   ol_class_tests 
      ON stt_test_num = test_num  
WHERE
   student_test_answer_id IS NULL   

   -- added this: replace test_id with real column 
   AND ***test_id*** NOT IN (
      SELECT
         test_id 
      FROM
         tests      
      JOIN
         test_questions 
            ON test_id= tq_test_id      
      WHERE
         type= 'THE_TYPE'      
      GROUP BY
         test_id      
      HAVING
         COUNT(*) = 1  
   )

---

第二个问题是什么？我在这里只看到一个查询，没有子查询。此外，精确模式的SQLFIDLE也会有所帮助

不管怎么说，我想你需要某种形式的左撇子。它看起来像这样：

(SELECT test_id, COUNT(*) AS theCount FROM tests
JOIN test_questions ON test_id= tq_test_id
WHERE type= 'THE_TYPE'
GROUP BY test_id
HAVING theCount = 1) outer
LEFT JOIN (
      [OtherQuery]
) a ON outer.test_id = a.test_id 
WHERE a.test_id IS NULL

select     test.test_id, count(*) as theCount
from       tests test
join       test_questions tq
on         tq.test_id = test.test_id
left join  tests excluded_test
on         excluded_test.test_id = test.test_id
where      tq.type = 'THE_TYPE'
and        << Some condition that explains what excluded_test is >>
and        excluded_test.test_id is null

SELECT
   DISTINCT test_title,
   olc_stt_i_num 
FROM
   student_tests  
LEFT JOIN
   student_test_answers 
      ON olc_sta_i_stt_num = olc_stt_i_num   
INNER JOIN
   ol_class_tests 
      ON stt_test_num = test_num  
WHERE
   student_test_answer_id IS NULL   

   -- added this: replace test_id with real column 
   AND ***test_id*** NOT IN (
      SELECT
         test_id 
      FROM
         tests      
      JOIN
         test_questions 
            ON test_id= tq_test_id      
      WHERE
         type= 'THE_TYPE'      
      GROUP BY
         test_id      
      HAVING
         COUNT(*) = 1  
   )

选择test.test\u id，count（*）作为计数
从测试
加入测试题tq
在tq.test\u id=test.test\u id上
左连接测试已排除。\u测试
在排除的测试上。测试id=测试。测试id
其中tq.type='THE_type'
和>
排除的测试id为空

---

编辑：是的，原来的问题中肯定有很多细节遗漏了（在某些方面已经被修复），现在仍然没有。了解示例的完整表结构在这里很重要，因此很难提供一个好的具体答案。

如注释中所述，您应该能够这样做：

(SELECT test_id, COUNT(*) AS theCount FROM tests
JOIN test_questions ON test_id= tq_test_id
WHERE type= 'THE_TYPE'
GROUP BY test_id
HAVING theCount = 1) outer
LEFT JOIN (
      [OtherQuery]
) a ON outer.test_id = a.test_id 
WHERE a.test_id IS NULL

select     test.test_id, count(*) as theCount
from       tests test
join       test_questions tq
on         tq.test_id = test.test_id
left join  tests excluded_test
on         excluded_test.test_id = test.test_id
where      tq.type = 'THE_TYPE'
and        << Some condition that explains what excluded_test is >>
and        excluded_test.test_id is null

SELECT
   DISTINCT test_title,
   olc_stt_i_num 
FROM
   student_tests  
LEFT JOIN
   student_test_answers 
      ON olc_sta_i_stt_num = olc_stt_i_num   
INNER JOIN
   ol_class_tests 
      ON stt_test_num = test_num  
WHERE
   student_test_answer_id IS NULL   

   -- added this: replace test_id with real column 
   AND ***test_id*** NOT IN (
      SELECT
         test_id 
      FROM
         tests      
      JOIN
         test_questions 
            ON test_id= tq_test_id      
      WHERE
         type= 'THE_TYPE'      
      GROUP BY
         test_id      
      HAVING
         COUNT(*) = 1  
   )

---

这是我的答案。左外部联接为您提供了参与者（测试）。如果测试题中没有匹配项，那么它仍将返回测试行，但测试题为null。因此，如果您然后查找任何为空的test_question.test_id，您将得到您要查找的内容

我也会在yourcount子句中详细说明，而不是仅仅为了确保mysql知道您真正想要计数的内容而进行计数（*）

create database test;
use test;

create table test
(
    test_id int, 
    `the_type` varchar(20)
);

create table test_questions
(
    test_question_id int,
    test_id int,
    `the_type` varchar(20)
);

insert into test values (1, 'history');
insert into test values (2, 'chemistry');
insert into test values (3, 'reading');

insert into test_questions values (1, 1, 'hard question');
insert into test_questions values (2, 1, 'medium question');
insert into test_questions values (3, 2, 'hard question');
insert into test_questions values (4, 2, 'easy question');

select * from test;
select * from test_questions;

select t.test_id, count(distinct t.test_id)
from test t
left outer join test_questions tq on tq.test_id = t.test_id
where
    tq.test_id is null
group by
    t.test_id

---

在没有看到您的实际查询的情况下，我冒昧地猜测您的子查询是不相关的。请发布您的真实查询、数据样本和预期结果。您的解释不太清楚，您的查询也不清楚：

test\u id=tq\u test\u id

-我们不知道这些列属于哪个表。您到底是如何尝试

not IN（）

？如果要将此查询用作子查询，则不需要结果集中的计数。@Philipp嗯，我无法使用此计数，因为计数/分组依据，所以我不得不放弃此想法。是的，但是如果要从其他结果集中排除数据，您需要计数做什么？你可以保留having子句，但不是在别名上，而是在实际计数（*）我只是想知道：

test\u id

列是否存在于

student\u tests

或

student\u tests

中？我在什么地方漏掉了吗？不，它只是作为实际列的占位符，带有id，可以这样标记。OP暗示在子查询的select中只有count（*）一列打乱了他的查询我很确定这就是我所需要的。我不知道他的查询返回什么，但它的结构似乎在工作。我想上面的其他人可能也这么做了。当然，我在主查询中添加了“LEFT JOIN（ANSWER）”。以上只是我需要的相关部分。@Alex讽刺我猜？我要说，其他人似乎花了更多的时间在它和格式。但我想我会选择对我有用的答案。社区将投票选出我所期待的最好的。