SQL UNION 返回多于列

Question

我有以下 sql 语句。将结果全部集中在一列中。我想要的是让仪表板标题返回一次，然后每个图表中的一行属于另一列中的仪表板。

SELECT 
    DashBoards.Title AS [Dash Board] 
FROM DashBoards 
GROUP BY DashBoards.Title 

UNION ALL

SELECT  
    Charts.Title AS Chart
FROM Charts 
INNER JOIN DashBoardCharts 
    ON Charts.ID = DashBoardCharts.ChartID 
INNER JOIN DashBoards 
    ON DashBoardCharts.DashBoardID = DashBoards.DashBoardID

此查询涉及三个表：

CREATE TABLE Dashboards (
    DashboardID INTEGER NOT NULL PRIMARY KEY,
    Title CHAR(50) NOT NULL,
    ISDEFAULT BIT NOT NULL,
    CompanyID INTEGER NULL
);    
INSERT INTO Dashboards
VALUES (1,'Main DashBoard', 1, NULL);

CREATE TABLE Charts (   
    ID INTEGER NOT NULL PRIMARY KEY,
    Title CHAR(50) NOT NULL,
    SPName CHAR(50) NOT NULL,
    XField CHAR(50) NOT NULL,
    YField CHAR(50) NOT NULL
);    
INSERT INTO Charts
VALUES (1,'Alerting and Monitoring', 'spGetData', 'SumType', 'SumAmount');

CREATE TABLE DashboardCharts (
    DashBoardID INTEGER NOT NULL FOREIGN KEY REFERENCES Dashboards (DashboardID),
    ChartID INTEGER NOT NULL FOREIGN KEY REFERENCES Charts (ID)
);
INSERT INTO DashboardCharts
VALUES (1, 1); 

我正在寻找的结果是这样的。

仪表板图表
“主仪表板”、“销售分析”
“警报和监控”
“另一个仪表板”、“成本管理”
'结算管理'

I.E.只返回一次仪表板标题以及属于该仪表板的所有图表。

Answer 1

SELECT d.Title AS Dashboard, c.Title AS Chart
FROM  Dashboards AS d
      INNER JOIN DashboardCharts AS dc
        ON d.DashboardID = dc.DashboardID
      INNER JOIN Charts AS c
        ON dc.ChartID = c.ChartID

我根据提供的信息对您的表结构和数据做了一些假设。见SQL Fiddle。

对于未来的 SQL 问题，了解表结构和数据会很有帮助。即使是简单的表格和数据的 CSV 表示形式，也可以极大地提高您收到的答案的质量，例如：

仪表板表

DashboardID,Title
1,'Main Dashboard'
2,'Alerting and Monitoring'