Query for comma-separated ids to comma-separated values

Question

I have 2 tables

Departments

ID  Dept
---------
1   HR
2   Accts
3   IT

Employee

ID Name     Depts
-------------------
1  Kevin     2,1
2  Michelle  1
3  Troy      1,3
4  Rheesa    2,3,1

I am looking for an output like the following with a SQL query.

Employee depts

ID Name      Depts
-------------------------
 1 Kevin     Accts,HR
 2 Michelle  HR
 3 Troy      HR,IT
 4 Rheesa    Accts,IT,HR

I have tried the following that join s with depts but results in one row for each dept only. How do i get the above results using a query?

select 
    name, depts, dept 
from 
    employee
CROSS APPLY  
    dbo.split_list(employee.depts ,',') split
inner join 
    dbo.department on  depts= split.value
order by 
    name

Answer 1

DECLARE @Departments TABLE 
(
  ID INT PRIMARY KEY, 
  Dept VARCHAR(32) NOT NULL UNIQUE
);

DECLARE @Employees TABLE
(
  ID INT PRIMARY KEY,
  Name NVARCHAR(64) NOT NULL,
  Depts VARCHAR(255) NOT NULL
);

INSERT @Departments VALUES 
  (1,'HR'),  (2,'Accts'),  (3,'IT');

INSERT @Employees VALUES
  (1,'Kevin','2,1'), (2,'Michelle','1'),
  (3,'Troy','1,3'),  (4,'Rheesa','2,3,1');

SELECT ID, Name, Depts = STUFF((SELECT ',' + d.Dept 
    FROM @Departments AS d
    INNER JOIN @Employees AS ei
    ON ',' + ei.Depts + ',' LIKE '%,' + CONVERT(VARCHAR(12), d.id) + ',%'
    WHERE ei.ID = e.ID
    ORDER BY Dept
    FOR XML PATH, 
    TYPE).value(N'/text().[1]', N'nvarchar(max)'), 1, 1, N'')
FROM @Employees AS e
ORDER BY ID;

The results don't quite match your required results, as the ordering is deterministic (ordered by department name):

ID      Name        Depts
----    --------    ----
1       Kevin       Accts,HR
2       Michelle    HR
3       Troy        HR,IT
4       Rheesa      Accts,HR,IT

If you want them ordered by the appearance in the comma-separated list, just change:

ORDER BY Dept

To:

ORDER BY CHARINDEX( ',' + CONVERT(VARCHAR(12), d.id) + ',', ',' + ei.Depts + ',')

Results:

ID      Name        Depts
----    --------    ----
1       Kevin       Accts,HR
2       Michelle    HR
3       Troy        HR,IT
4       Rheesa      Accts,IT,HR -- this is the only one affected as it turns out

However, in reality, you should normalize your database. This is an absolute nightmare.

Answer 2

Looking beyond how you're storing your data, let me try to help you out.

Well, you're asking a lot of questions here. First, to split the data, you can format it as XML and use CROSS APPLY -- trick I saw a while back that didn't require built in functions.

That will convert your comma delimited string to a list of strings. You can then use FOR XML to put them back together.

Give this a shot:

SELECT
   E.Id, 
   E.Name, 
   STUFF(
        (
        SELECT ',' +  D.Department AS [text()]
        FROM  (
           SELECT A.[id],  
             Split.a.value('.', 'VARCHAR(100)') AS DeptId  
           FROM  
              (SELECT [id],  
                 CAST ('<M>' + REPLACE(Depts, ',', '</M><M>') + '</M>' AS XML) AS String  
              FROM  Employee
          ) AS A 
        CROSS APPLY String.nodes ('/M') AS Split(a)) A 
        JOIN Departments D ON A.DeptId = D.Id
        WHERE E.Id = A.Id
        FOR XML PATH('')
        ), 1, 1, '') AS Departments
FROM Employee E

And here is the SQL Fiddle.

Good luck.