Question

我有一张看起来像这样的表

ailment_symptoms 
+----+----------+-----------+
|id  |ailment_id|symptom_id |
+----+----------+-----------+
|1   | 1        |  1        |
|2   | 1        |  2        |
|3   | 2        |  1        |
|4   | 2        |  3        |
|5   | 3        |  3        |
|6   | 3        |  2        |
|7   | 4        |  1        |
|8   | 4        |  2        |
+----+----------+-----------+

我想选择所有ailment_id，例如symptom_id=1 AND symptom id = 2，有人建议使用以下代码。

SELECT s.ailment_id
FROM ailment_symptoms s
WHERE s.symptom_id in (1, 2)
GROUP BY s.ailment_id
HAVING COUNT(DISTINCT s.symptom_id) = 2

我现在的问题是，假设该表有另一个名为symptom_intesity的列，并且我想选择一个疾病ID (symptom_id1 = 1 AND s1.symptom _intensity = 'acute') AND (symptom_id2 = 2 AND symptom_intensity='slight') AND (...) OR (...) 像那样。使用多个自联接，它看起来像这样：

SELECT t1.ailment_id
FROM ailment_symptoms t1
INNER JOIN ailment_symptoms t2 ON t1.ailment_id = t2.ailment_id
INNER JOIN ailment_symptoms t3 ON t1.ailment_id = t3.ailment_id
INNER JOIN ailment_symptoms t4 ON t1.ailment_id = t4.ailment_id
   /*---- more inner joins as there are symptoms ----*/
WHERE (t1.symptom_id =  '1' AND t1.intensity = 'acute')
AND (t2.symptom_id =  '10')
AND (t3.symptom_id =  '3' AND t2.intensity = 'slight')
AND (t4.symptom_id =  '4')
 /*----and so on ----/

如何使用第一个查询的结构实现此目的。我也会感谢您的解释，因此我可以根据自己的需要进行修改。谢谢。

Answer 1

如果我已正确理解你的目标，我通常在这种情况下使用连接，即当逻辑表达式取决于某些条件时：

     SELECT ailment_id
      FROM ailment_symptoms 
     WHERE symptom_id||symptom_intesity='1acute' OR symptom_id||symptom_intesity='2slight' OR symptom_id = '10' OR symptom_id =  '4'
    GROUP BY ailment_id
    HAVING COUNT(DISTINCT symptom_id) = 2

Mysql：使用HAVING与其他条件而不是Multiple Self Join

1 个答案: