Retrieve A Recordset From One Table Based On The CSV Values In The Field Of Another

Hello!

I have 2 tables, one that contains a set of codes and their definitions, and another where each record has a field that contains several of these codes separated by commas:

Tab1

SubCode | Definition
---------------
S100 | Def of S100
S101 | Def of S101
S102 | Def of S102

Tab2

DepID | Purpcode |SubCodes
-----------------------------
1 | P100 | S100,S101,S102
1 | P101 | S100, S101
2 | P101 | S100,S102

I'm trying to create a query against Tab1 so that it retrieves a recordset of Subcodes and definitions based on the contents of the Subcodes field for a record in Tab2. I've tried this using a subquery, as follows:

SELECT SubCode ,Definition
FROM Tab1
WHERE SubjectCode IN
(SELECT CHAR(39) + REPLACE(SubjectCodes, CHAR(44), CHAR(39 + CHAR(44)+ CHAR(39)) + CHAR(39)
FROM Tab2
WHERE DepID = 1 AND PurposeCode = 'P101')

The subquery will return: 'S100','S101' and I expect the final recordset to be:

SubCode | Definition
---------------
S100 | Def of S100
S101 | Def of S101

However, it's not returning any records. If I execute the subquery separately and then plug its results into the main query e.g.

SELECT SubCode ,Definition
FROM Tab1
WHERE SubjectCode IN ('S100','S101')

it returns the expected recordset. Does anyone have any pointers? It's driving me nuts..

Cheers
Greg

Complete DDL, Sample Data, and Query below:


if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[SubjectCodeDefinition]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[SubjectCodeDefinition]
GO

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[DepartmentReturn]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[DepartmentReturn]
GO

CREATE TABLE [dbo].[SubjectCodeDefinition] (
[SubjectCode] [varchar] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL ,
[Definition] [varchar] (100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL
) ON [PRIMARY]
GO

CREATE TABLE [dbo].[DepartmentReturn] (
[DeptID] [int] NULL ,
[PurposeCode] [varchar] (10) COLLATE SQL_Latin1_General_CP1_CI_AS NULL ,
[SubjectCodes] [varchar] (250) COLLATE SQL_Latin1_General_CP1_CI_AS NULL ,
) ON [PRIMARY]
GO

INSERT INTO SubjectCodeDefinition(SubjectCode, Definition)
SELECT 'S100', 'Definition of Code S100' UNION ALL
SELECT 'S101', 'Definition of Code S101' UNION ALL
SELECT 'S102', 'Definition of Code S102' UNION ALL
SELECT 'S103', 'Definition of Code S103' UNION ALL
SELECT 'S104', 'Definition of Code S104' UNION ALL
SELECT 'S105', 'Definition of Code S105'
GO

INSERT INTO DepartmentReturn(DeptID,PurposeCode,SubjectCodes)
SELECT 1,'P100','S100,S101,S104' UNION ALL
SELECT 1,'P101','S102,S103' UNION ALL
SELECT 1,'P102','S100,S101,S105' UNION ALL
SELECT 2,'P100','S100,S101,S104,S105' UNION ALL
SELECT 2,'P103','S103,S104,S105' UNION ALL
SELECT 3,'P100','S100,S102,S104'
GO

SELECT SubjectCode ,Definition
FROM SubjectCodeDefinition
WHERE SubjectCode IN
(SELECT CHAR(39) + REPLACE(SubjectCodes, CHAR(44), CHAR(39)+ CHAR(44)+ CHAR(39)) + CHAR(39)
FROM DepartmentReturn
WHERE DeptID = 1 AND PurposeCode = 'P102')