Left Outer Join, Multi Tables, To Populate Checkboxes in Classic ASP Application

Question

I've been working with several tables in sql server 2008, and the data is used in a Classic ASP application. The following query (please see below) has been used to populate an 'update' page with checkboxes. The first table (KSA), populates the checkboxes, while the second table (KSA_Out) provides the checkboxes that the user checked. There is a set of these KSA checkboxes for each Objective, and the problem I'm having is that I would like for the KSA Left Join to still populate the form's checkboxes, even if there are no matches in the joined tables.

The idea behind the application is this: There is a page with a table: a row for each objective, and a column for each outcome. The table is populated by the Objectives table and the Outcomes table, with an "Add/Edit" link in each cell, and a URL with Querystring that passes the ObjectiveID and the OutcomeID to the next page, which updates the Objective/Outcome combination.

On the update page, there is a query that populates a form with checkboxes. The KSA table populates the list items, while the OutcomesKSA table provides any previously user-entered data, in the form of a checked checkbox (the OutcomesKSA.KSA_Value field, which is boolean). The ObjOut table is a junction table that ties in the Objectives and Outcomes tables.

In the application, I would like to get only the data for a certain Objective/Outcome combination, if the user-entered checkbox data exists (the OutcomesKSA.KSA_Value field, which is boolean), yet still get only the form list from the KSA table, if no data has been entered in the OutcomesKSA table.

Currently, nothing is populated, with the query I'm using (please see below) .

Thanks for any help in this.

Here's how the data would appear, from table to table, to show how the data is dispersed and related (I've only included PKs and FKs, to show their relationships):

Objectives table
ID
5

Outcomes table
ID
4


ObjOut table
ID|ObjectiveID|OutcomeID
1|5|4

OutcomesKSA table
ID|ObjOutID|KSA_ID 
2|1|1
3|1|2
4|1|3


KSA table
ID
1
2
3

The query:

SELECT 
KSA.ID as KSA_ID, KSA.KSA_Version, KSA.KSA_Sort_Order_Number, 
KSA.KSA_Outcome_Number, KSA.KSA_Category as KSA_KSA_Category, 
KSA.KSA_Category_Sub_Num, KSA.KSA_Category_Sub_Num_Descr, 
KSA.KSA_Category_Sub_Num_Sub_Alpha, KSA.KSA_Category_Sub_Num_Sub_Alpha_Descr, 
KSA.KSA_ID as KSA_KSA_ID, KSA.KSA_Descr_Combined as KSA_KSA_Descr_Combined, 
KSA.LastUpdate, KSA.Date_Created, 

OutcomesKSA.KSA_ID as OutcomesKSA_KSA_ID,OutcomesKSA.KSA_Value as OutcomesKSA_KSA_Value,OutcomesKSA.ObjOutID, 

ObjOut.ObjectiveID, ObjOut.OutcomeID, 

Objectives.ID as Obj_Obj_ID 


FROM 
KSA
LEFT OUTER JOIN 
OutcomesKSA
ON 
KSA.ID=OutcomesKSA.KSA_ID 
INNER JOIN 
ObjOut
ON 
OutcomesKSA.ObjOutID=ObjOut.ID 
INNER JOIN 
Objectives
ON 
ObjOut.ObjectiveID=Objectives.ID 

WHERE 
KSA.KSA_Outcome_Number ='1' 
AND 
KSA.KSA_Category ='k' 
AND 
Objectives.ID ='29' 

ORDER BY KSA.KSA_Sort_Order_Number ASC; 

The tables:

SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[Objectives](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [CourseID] [int] NOT NULL,
    [Objective] [varchar](max) NULL,
    [LastUpdate] [datetime] NULL,
    [Date_Created] [datetime] NULL,
 CONSTRAINT [PK_Objectives] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO

ALTER TABLE [dbo].[Objectives]  WITH NOCHECK ADD  CONSTRAINT [FK_Objectives_Courses] FOREIGN KEY([CourseID])
REFERENCES [dbo].[Courses] ([CourseID])
ON UPDATE CASCADE
GO

ALTER TABLE [dbo].[Objectives] CHECK CONSTRAINT [FK_Objectives_Courses]
GO

ALTER TABLE [dbo].[Objectives] ADD  CONSTRAINT [DF_Objectives_Date_Created]  DEFAULT (getdate()) FOR [Date_Created]
GO

=============

SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[Outcomes](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [OutcomeGroup] [varchar](50) NULL,
    [OutcomeType] [varchar](50) NULL,
    [OutcomeNumber] [int] NULL,
    [OutcomeName] [varchar](500) NULL,
    [OutcomeDescription] [varchar](max) NULL,
    [OutcomeVersionYear] [varchar](50) NULL,
    [OutcomeVersionSemester] [varchar](50) NULL,
    [LastUpdate] [datetime] NULL,
    [Date_Created] [datetime] NULL,
 CONSTRAINT [PK_Outcomes] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO

ALTER TABLE [dbo].[Outcomes] ADD  CONSTRAINT [DF_Outcomes_Date_Created]  DEFAULT (getdate()) FOR [Date_Created]
GO


==========


SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE TABLE [dbo].[ObjOut](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [ObjectiveID] [int] NULL,
    [OutcomeID] [int] NULL,
    [LastUpdate] [datetime] NULL,
    [Date_Created] [datetime] NULL,
 CONSTRAINT [PK_ObjOut] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[ObjOut]  WITH CHECK ADD  CONSTRAINT [FK_ObjOut_Objectives] FOREIGN KEY([ObjectiveID])
REFERENCES [dbo].[Objectives] ([ID])
ON UPDATE CASCADE
ON DELETE CASCADE
GO

ALTER TABLE [dbo].[ObjOut] CHECK CONSTRAINT [FK_ObjOut_Objectives]
GO

ALTER TABLE [dbo].[ObjOut]  WITH CHECK ADD  CONSTRAINT [FK_ObjOut_Outcomes] FOREIGN KEY([OutcomeID])
REFERENCES [dbo].[Outcomes] ([ID])
ON UPDATE CASCADE
ON DELETE CASCADE
GO

ALTER TABLE [dbo].[ObjOut] CHECK CONSTRAINT [FK_ObjOut_Outcomes]
GO

ALTER TABLE [dbo].[ObjOut] ADD  CONSTRAINT [DF_ObjOut_Date_Created]  DEFAULT (getdate()) FOR [Date_Created]
GO







===========

SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE TABLE [dbo].[OutcomesKSA](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [ObjOutID] [int] NOT NULL,
    [KSA_ID] [int] NULL,
    [KSA_Value] [bit] NULL,
    [LastUpdate] [datetime] NULL,
    [Date_Created] [datetime] NULL,
 CONSTRAINT [PK_OutcomesKSA] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[OutcomesKSA]  WITH CHECK ADD  CONSTRAINT [FK_OutcomesKSA_ObjOut] FOREIGN KEY([ObjOutID])
REFERENCES [dbo].[ObjOut] ([ID])
ON UPDATE CASCADE
ON DELETE CASCADE
GO

ALTER TABLE [dbo].[OutcomesKSA] CHECK CONSTRAINT [FK_OutcomesKSA_ObjOut]
GO

ALTER TABLE [dbo].[OutcomesKSA] ADD  CONSTRAINT [DF_OutcomesKSA_Date_Created]  DEFAULT (getdate()) FOR [Date_Created]



=========================







SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[KSA](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [KSA_Version] [varchar](50) NULL,
    [KSA_Sort_Order_Number] [int] NULL,
    [KSA_Outcome_Number] [varchar](50) NULL,
    [KSA_Outcome_Number_Sort] [varchar](50) NULL,
    [KSA_Category] [char](1) NULL,
    [KSA_Category_Sub_Num] [varchar](50) NULL,
    [KSA_Category_Sub_Num_Sort] [varchar](50) NULL,
    [KSA_Category_Sub_Num_Descr] [varchar](max) NULL,
    [KSA_Category_Sub_Num_Sub_Alpha] [char](1) NULL,
    [KSA_Category_Sub_Num_Sub_Alpha_Descr] [varchar](1000) NULL,
    [KSA_ID] [char](8) NULL,
    [KSA_ID_Sort] [char](8) NULL,
    [KSA_Descr_Combined] [varchar](max) NULL,
    [LastUpdate] [datetime] NULL,
    [Date_Created] [datetime] NULL,
 CONSTRAINT [PK_KSA] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO

ALTER TABLE [dbo].[KSA] ADD  CONSTRAINT [DF_KSA_Date_Created]  DEFAULT (getdate()) FOR [Date_Created]
GO

Answer 1

The later INNER JOINs are effectively turning the OUTER JOIN back into an INNER. You can structure the query so that multiple tables are INNER JOINed together and then that set is applied as an OUTER JOIN.

Also, the WHERE clause is applied after all of the joins and will filter the entire row, so with an OUTER JOIN there is a difference between placing the filter in the WHERE clause and in the ON clause.

A side note about coding style. While there are a lot of personal preferences in how code is formatted, it should generally have the goal of being easy to read and understand. I'd encourage you to consider a different format, both for when you are presenting the code to someone else, as well as when you try to understand what you wrote in 6 months.

Putting it all together, this should be more of what you want.

SELECT 
    KSA.ID as KSA_ID
    ,KSA.KSA_Version
    ,KSA.KSA_Sort_Order_Number
    ,KSA.KSA_Outcome_Number
    ,KSA.KSA_Category as KSA_KSA_Category
    ,KSA.KSA_Category_Sub_Num
    ,KSA.KSA_Category_Sub_Num_Descr
    ,KSA.KSA_Category_Sub_Num_Sub_Alpha
    ,KSA.KSA_Category_Sub_Num_Sub_Alpha_Descr
    ,KSA.KSA_ID as KSA_KSA_ID
    ,KSA.KSA_Descr_Combined as KSA_KSA_Descr_Combined
    ,KSA.LastUpdate
    ,KSA.Date_Created
    ,OutcomesKSA.KSA_ID as OutcomesKSA_KSA_ID
    ,OutcomesKSA.KSA_Value as OutcomesKSA_KSA_Value
    ,OutcomesKSA.ObjOutID
    ,ObjOut.ObjectiveID
    ,ObjOut.OutcomeID
    ,Objectives.ID as Obj_Obj_ID 
FROM 
    KSA
    LEFT OUTER JOIN (
        OutcomesKSA
        INNER JOIN ObjOut
            ON OutcomesKSA.ObjOutID = ObjOut.ID 
        INNER JOIN Objectives
            ON ObjOut.ObjectiveID = Objectives.ID 
    ) ON KSA.ID = OutcomesKSA.KSA_ID 
        AND Objectives.ID = 29 --filter
WHERE 
    KSA.KSA_Outcome_Number = '1' 
    AND KSA.KSA_Category = 'k' 
ORDER BY KSA.KSA_Sort_Order_Number;