Question

我的目标是在Entity表上为包含2个人的所有家庭计算和设置HouseholdName字段。我正在使用SQL Server 2012，我必须使用的模式是：

CREATE TABLE Entity
(
   EID INT, --PK
   PID INT, --FK to Person.[Person ID]
   HouseholdID VARCHAR(50), 
   HouseholdName VARCHAR(300)
);

CREATE TABLE Person
(
   [Person ID] INT, 
   FirstName   VARCHAR(30), 
   LastName    VARCHAR(30)
);

INSERT INTO Entity VALUES (1,1,'HH1',NULL);
INSERT INTO Entity VALUES (2,2,'HH1',NULL);
INSERT INTO Entity VALUES (3,3,'HH2',NULL);
INSERT INTO Entity VALUES (4,4,'HH2',NULL);
INSERT INTO Entity VALUES (5,5,'HH3',NULL);

INSERT INTO Person VALUES (1,'Jane', 'Doe');
INSERT INTO Person VALUES (2,'Joe',  'Doe');
INSERT INTO Person VALUES (3,'Sara', 'Dillin');
INSERT INTO Person VALUES (4,'Bill', 'Smith');
INSERT INTO Person VALUES (5,'Ted',  'Loner');

计算家喻户晓的逻辑是这样的：如果两个姓氏相同，例如对于HouseholdID HH1，则家喻户晓的姓名应为'Jane＆amp; Joe Doe'。如果姓氏不同，例如在HH2中，它的格式应为'Sara Dillin＆amp;比尔史密斯'

我可以识别这些人并按顺序得到他们：

SELECT FirstName,LastName,HouseholdID
FROM Entity e
JOIN Person p ON p.[Person ID]=e.[PID]
WHERE HouseholdID IN  --HHs of 2 people
(
   SELECT DISTINCT HouseholdID
   FROM Entity e
   JOIN Person p ON p.[Person ID]=e.[PID]
   GROUP BY HouseholdID HAVING COUNT(*)=2
)
ORDER BY HouseholdID

但是我坚持过去了。从像C＃这样的过程语言我知道如何解决这个问题，但它很慢。我希望能够以更快的SQL方式完成它。

Answer 1

抱歉，我稍微更改了字段名称，以便于编码。以下查询将为您提供所需内容：

SELECT 
  e1.HouseholdID,
  CASE WHEN p2.LastName =  p1.LastName THEN  p1.FirstName + ' & ' + p2.FirstName + ' ' + p2.LastName
       ELSE p1.FirstName + ' ' + p1.LastName + ' & ' + p2.FirstName + ' ' + p2.LastName END AS HouseholdName,
  p1.FirstName,
  p1.LastName,
  p2.FirstName as p2FirstName,
  p2.LastName as p2LastName
FROM 
 Person p1 
 INNER JOIN Entity e1 ON 
   p1.id = e1.PID
 LEFT JOIN Entity e2 
   ON e1.HouseholdID = e2.HouseholdID AND e1.id < e2.id
 LEFT JOIN Person p2
   ON e2.PID = p2.id
WHERE e2.ID IS NOT NULL
  AND NOT EXISTS 
    ( SELECT * FROM Entity e3 
      WHERE e1.HouseholdID = e3.HouseholdID
      AND NOT e3.id IN (e1.id, ISNULL(e2.id, 0))
    )

http://sqlfiddle.com/#!3/c8dd9/15

根据家庭中的记录设置家庭名称字段

1 个答案: