Question

I’ve got two tables:

TableA ------ ID, Name  TableB ------ ID, SomeColumn, TableA_ID (FK for TableA) 

The relationship is one row of TableA – many of TableB.

Now, I want to see a result like this:

ID     Name      SomeColumn  1.     ABC       X, Y, Z (these are three different rows) 2.     MNO       R, S 

This won’t work (multiple results in a subquery):

SELECT ID,        Name,         (SELECT SomeColumn FROM TableB WHERE F_ID=TableA.ID) FROM TableA 

This is a trivial problem if I do the processing on the client side. But this will mean I will have to run X queries on every page, where X is the number of results of TableA.

Note that I can’t simply do a GROUP BY or something similar, as it will return multiple results for rows of TableA.

I’m not sure if a UDF, utilizing COALESCE or something similar might work?

Answer 1

1. Create the UDF:

CREATE FUNCTION CombineValues (     @FK_ID INT -- The foreign key from TableA which is used                 -- to fetch corresponding records ) RETURNS VARCHAR(8000) AS BEGIN DECLARE @SomeColumnList VARCHAR(8000);  SELECT @SomeColumnList =     COALESCE(@SomeColumnList + ', ', '') + CAST(SomeColumn AS varchar(20))  FROM TableB C WHERE C.FK_ID = @FK_ID;  RETURN  (     SELECT @SomeColumnList ) END 

2. Use in subquery:

SELECT ID, Name, dbo.CombineValues(FK_ID) FROM TableA 

3. If you are using stored procedure you can do like this:

CREATE PROCEDURE GetCombinedValues  @FK_ID int As BEGIN DECLARE @SomeColumnList VARCHAR(800) SELECT @SomeColumnList =     COALESCE(@SomeColumnList + ', ', '') + CAST(SomeColumn AS varchar(20))  FROM TableB WHERE FK_ID = @FK_ID   Select *, @SomeColumnList as SelectedIds     FROM          TableA     WHERE          FK_ID = @FK_ID  END