Sql server 从第一个表中获取所有数据，即使联接表中不存在联接项

我有四个表，分类账，会计科目表，会计科目表，会计科目表

CREATE TABLE AccDetail (DetailID int,
                        MasterID int,
                        LedgerID int,
                        Credit decimal(18, 2));
INSERT INTO AccDetail
VALUES (1, 1, 1, 500), (2,2,2,1000);

CREATE TABLE Ledgers (ID int,
                      Name varchar(10),
                      AccGroupID int);
INSERT INTO Ledgers
VALUES (1, 'A', 1),
       (2, 'B', 1);

CREATE TABLE AccMaster (MasterID int,
                        Date date);
INSERT INTO AccMaster
VALUES (1, '2019-11-04'),
       (2, '2019-11-03');

CREATE TABLE AccGroup (ID int,
                       Name varchar(10));
INSERT INTO AccGroup
VALUES (1, 'Accounts'),
       (2, 'Others');

SELECT AL.Name,
       SUM(AD.Credit)
FROM AccDetail AD
     LEFT OUTER JOIN Ledgers AL ON AL.ID = AD.LedgerID
     LEFT OUTER JOIN AccMaster AM ON AM.MasterID = AD.MasterID
     LEFT OUTER JOIN AccGroup AG ON AG.ID = AL.AccGroupID
WHERE AM.Date = '2019-11-04'
GROUP BY AL.Name;

即使分类账表中有两个分录，我也只得到分类账表中一个分录的结果。这是因为其他表中没有对应的分类账条目。我找到了很多关于左连接和右连接的答案，但是没有一个符合我的愿望

我想从分类账表中获取所有条目，即使其他表中没有该分类账的数据

我想得到的结果

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MS SQL Server 2017架构设置：

CREATE TABLE AccDetail (DetailID int,
                        MasterID int,
                        LedgerID int,
                        Credit decimal(18, 2));
INSERT INTO AccDetail
VALUES (1, 1, 1, 500);

CREATE TABLE Ledgers (ID int,
                      Name varchar(10),
                      AccGroupID int);
INSERT INTO Ledgers
VALUES (1, 'A', 1),
       (2, 'B', 1);

CREATE TABLE AccMaster (MasterID int,
                        Date date);
INSERT INTO AccMaster
VALUES (1, '2019-11-04'),
       (2, '2019-11-03');

CREATE TABLE AccGroup (ID int,
                       Name varchar(10));
INSERT INTO AccGroup
VALUES (1, 'Accounts'),
       (2, 'Others');

SELECT AL.Name,
       ISNULL(SUM(AD.Credit),0) AS SumOfCredits
FROM  Ledgers AL 
     LEFT OUTER JOIN AccDetail AD ON AL.ID = AD.LedgerID
     LEFT OUTER JOIN AccMaster AM ON AM.MasterID = AD.MasterID
     LEFT OUTER JOIN AccGroup AG ON AG.ID = AL.AccGroupID
     WHERE AM.Date = '2019-11-04' OR AM.Date IS NULL
GROUP BY AL.Name

| Name | SumOfCredits |
|------|--------------|
|    A |          500 |
|    B |            0 |

查询1：

CREATE TABLE AccDetail (DetailID int,
                        MasterID int,
                        LedgerID int,
                        Credit decimal(18, 2));
INSERT INTO AccDetail
VALUES (1, 1, 1, 500);

CREATE TABLE Ledgers (ID int,
                      Name varchar(10),
                      AccGroupID int);
INSERT INTO Ledgers
VALUES (1, 'A', 1),
       (2, 'B', 1);

CREATE TABLE AccMaster (MasterID int,
                        Date date);
INSERT INTO AccMaster
VALUES (1, '2019-11-04'),
       (2, '2019-11-03');

CREATE TABLE AccGroup (ID int,
                       Name varchar(10));
INSERT INTO AccGroup
VALUES (1, 'Accounts'),
       (2, 'Others');

SELECT AL.Name,
       ISNULL(SUM(AD.Credit),0) AS SumOfCredits
FROM  Ledgers AL 
     LEFT OUTER JOIN AccDetail AD ON AL.ID = AD.LedgerID
     LEFT OUTER JOIN AccMaster AM ON AM.MasterID = AD.MasterID
     LEFT OUTER JOIN AccGroup AG ON AG.ID = AL.AccGroupID
     WHERE AM.Date = '2019-11-04' OR AM.Date IS NULL
GROUP BY AL.Name

| Name | SumOfCredits |
|------|--------------|
|    A |          500 |
|    B |            0 |

：

CREATE TABLE AccDetail (DetailID int,
                        MasterID int,
                        LedgerID int,
                        Credit decimal(18, 2));
INSERT INTO AccDetail
VALUES (1, 1, 1, 500);

CREATE TABLE Ledgers (ID int,
                      Name varchar(10),
                      AccGroupID int);
INSERT INTO Ledgers
VALUES (1, 'A', 1),
       (2, 'B', 1);

CREATE TABLE AccMaster (MasterID int,
                        Date date);
INSERT INTO AccMaster
VALUES (1, '2019-11-04'),
       (2, '2019-11-03');

CREATE TABLE AccGroup (ID int,
                       Name varchar(10));
INSERT INTO AccGroup
VALUES (1, 'Accounts'),
       (2, 'Others');

SELECT AL.Name,
       ISNULL(SUM(AD.Credit),0) AS SumOfCredits
FROM  Ledgers AL 
     LEFT OUTER JOIN AccDetail AD ON AL.ID = AD.LedgerID
     LEFT OUTER JOIN AccMaster AM ON AM.MasterID = AD.MasterID
     LEFT OUTER JOIN AccGroup AG ON AG.ID = AL.AccGroupID
     WHERE AM.Date = '2019-11-04' OR AM.Date IS NULL
GROUP BY AL.Name

| Name | SumOfCredits |
|------|--------------|
|    A |          500 |
|    B |            0 |

---

你能分享你的输入和期望的输出吗？为什么你会期望多行

AccDetail

只有一行。为什么要加入accmaster和accgroup？你在查询中不使用它们中的任何内容？我删除了findle并将DDL和DML放入你的问题中，@faheemKurikkal，由于用户不应期望访问其他站点来回答您的问题。“我希望从分类账表中获取所有条目”-那么您需要从分类账而不是accdetail中驾驶。如果AccMaster没有where条件，您的答案是正确的。请检查更新的问题。AccMaster.Date有一个where条件。就我个人而言，我想把

AM.Date

上的子句移到

上的
上。您的两个查询@xXx都不起作用。where条件很重要查询1和查询2是什么？PS这个问题并没有说通常需要什么样的输出，那么为什么这个答案的任何部分都应该是答案呢？PS不清楚的问题应该被否决、否决和评论，以要求清楚，而不是猜测。@faheemKurikkal你在sqlfiddle上检查过我的答案了吗？它只给出一个分类账“A”的结果。即使没有B的条目，它也应该显示“B”0。问题并没有说明通常需要什么输出，所以为什么这应该是一个答案？PS不清楚的问题应被否决、否决和评论，以要求澄清，而不是猜测。