Loop through table variable and insert missing rows into new table variable - sql-server-2008

Question

I have a table variable which is populated with a number of rows. What I am trying to achieve, is to loop through each row of the table variable, see if the ID column exists in another standard table and add that row to a newly created table variable.
My code is as follows:
DECLARE
#Intervention_ID int
SET #Intervention_ID = 969
/*---Check if intervention has pre-requisites---*/
DECLARE #PreRequisites TABLE
(
[Intervention_ID] int
)
INSERT INTO #PreRequisites
(
[Intervention_ID]
)
SELECT IP.[Requisite_ID]
FROM DI_Intervention_Prerequisites IP
WHERE
IP.[Intervention_ID] = #Intervention_ID
AND IP.[Prerequisite] = 1
/*---Check if pre-requisites have been completed---*/
DECLARE #Result TABLE
(
[Type_ID] int
, [Type_Name] nvarchar(max)
, [Intervention_ID] int
, [Intervention_Name] nvarchar(max)
)
WHILE NOT EXISTS
(
SELECT TOP 1 1
FROM DI_Employee_Intervention EI
WHERE
EI.[Intervention_ID] = (SELECT [Intervention_ID] FROM #PreRequisites)
)
INSERT INTO #Result
(
[Type_ID]
, [Type_Name]
, [Intervention_ID]
, [Intervention_Name]
)
As you can see, I am stuck at the WHILE NOT EXISTS part of the code. What needs to happen is for each row within #PreRequisites that does not exist in DI_Employee_Intervention, that specific #PreRequisites row need to be inserted into #Result.

Answer 1

Why don't you just use a set-based approach instead of the RBAR (row-by-agonizing-row) procedural approach you have now??
Something like:
INSERT INTO #Result([Type_ID], [Type_Name], [Intervention_ID], [Intervention_Name])
SELECT
... (some columns to match the columns of #Result)......
FROM
dbo.DI_Intervention_Prerequisites IP
WHERE
IP.[Intervention_ID] = #Intervention_ID
AND IP.[Prerequisite] = 1
AND NOT EXISTS (SELECT *
FROM DI_Employee_Intervention EI
WHERE EI.[Intervention_ID] = IP.[Intervention_ID] )
or something like that (I didn't quite understand all your intermediate steps and why you take them....)