SQL - 選擇什麼不在聯合的第二個表中

Question

我有一個表「person」，一個關聯表「person_vaccination」和一個表「vaccination」。

我想讓失去疫苗的人失望，但到目前爲止，只有當我擁有身份證的時候，我才能得到它。

SELECT vac.VACCINATION_Name 
FROM VACCINATION vac 
WHERE vac.VACCINATION_NUMBER NOT IN 
(SELECT v.VACCINATION_NUMBER 
FROM PERSON per 
Join PERSON_VACCINATION pv ON per.PERSON_NUMBER = pv.PERSON_NUMBER 
JOIN VACCINATION v ON pv.VACCINATION_NUMBER = v.VACCINATION_NUMBER 
WHERE per.PERSON_NUMBER = 6) 

它工作正常，但我如何得到所有的人失蹤了接種疫苗？ （例如： 555，Vacccination 1 555，Vacccination 2 666，Vacccination 1）

Answer 1

SQL Fiddle

的Oracle 11g R2架構設置：

CREATE TABLE VACCINATION (VACCINATION_NUMBER, VACCINATION_NAME) AS 
      SELECT 1, 'Vac 1' FROM DUAL 
UNION ALL SELECT 2, 'Vac 2' FROM DUAL 
UNION ALL SELECT 3, 'Vac 3' FROM DUAL 
UNION ALL SELECT 4, 'Vac 4' FROM DUAL; 

CREATE TABLE PERSON_VACCINATION (VACCINATION_NUMBER, PERSON_NUMBER) AS 
      SELECT 1, 1 FROM DUAL 
UNION ALL SELECT 2, 1 FROM DUAL 
UNION ALL SELECT 3, 1 FROM DUAL 
UNION ALL SELECT 4, 1 FROM DUAL 
UNION ALL SELECT 1, 2 FROM DUAL 
UNION ALL SELECT 2, 2 FROM DUAL 
UNION ALL SELECT 3, 2 FROM DUAL; 

CREATE TABLE PERSON (PERSON_NUMBER, PERSON_NAME) AS 
      SELECT 1, 'P1' FROM DUAL 
UNION ALL SELECT 2, 'P2' FROM DUAL 
UNION ALL SELECT 3, 'P3' FROM DUAL; 

查詢1：

SELECT p.PERSON_NAME, 
     v.VACCINATION_NAME 
FROM VACCINATION v 
     CROSS JOIN 
     PERSON p 
WHERE NOT EXISTS (SELECT 1 
        FROM PERSON_VACCINATION pv 
        WHERE pv.VACCINATION_NUMBER = v.VACCINATION_NUMBER 
        AND pv.PERSON_NUMBER = p.PERSON_NUMBER) 
ORDER BY p.PERSON_NAME, 
     p.PERSON_NUMBER, 
     v.VACCINATION_NAME, 
     v.VACCINATION_NUMBER 

Results：

| PERSON_NAME | VACCINATION_NAME | 
|-------------|------------------| 
|   P2 |   Vac 4 | 
|   P3 |   Vac 1 | 
|   P3 |   Vac 2 | 
|   P3 |   Vac 3 | 
|   P3 |   Vac 4 | 

Answer 2

相反的INNER JOIN，你應該使用LEFT JOIN。

看看這個鏈接：http://www.w3schools.com/sql/sql_join_left.asp

Answer 3

如果你是後人們沒有接種疫苗的話，那麼你可以使用LEFT OUTER PERSON和PERSON_VACCINATION之間的連接，然後找到的所有條目，其中一個PERSON_VACCINATION列爲NULL。

SELECT PERSON_NUMBER 
FROM PERSON P 
LEFT OUTER JOIN 
PERSON_VACCINATION PV 
ON P.PERSON_NUMBER = PV.PERSON_NUMBER 
WHERE PV.PERSON_NUMBER IS NULL 

如果你不熟悉LEFT OUTER JOIN，它試圖找到PERSON_VACCINATION匹配的行爲親自每一行。如果沒有匹配的行，則它將PERSON行留在結果集中，併爲PERSON_VACCINATION表中的所有列顯示NULL值。

如果您正在尋找他們沒有的人員列表和疫苗接種，那麼@MT0的答案是正確的。您需要創建一個包含PERSON和VACCINATION（一個交叉連接）的所有可能組合的結果集，然後檢查PERSON_VACCINATION中實際存在哪些組合。任何不存在的條目都是你缺少的疫苗接種。