Question

I have three tables and a range of two dates:

Services
ServicesClients
ServicesClientsDone


@StartDate
@EndDate

Services:

ID | Name
1  | Supervisor
2  | Monitor
3  | Manufacturer

ServicesClients:

IDServiceClient | IDClient | IDService
1               | 1        | 1
2               | 1        | 2
3               | 2        | 2
4               | 2        | 3

ServicesClientsDone:

IDServiceClient | Period 
1               | 201208
3               | 201210

Period = YYYYMM

I need to insert into ServicesClientsDone the months range from @StartDate up @EndDate. I have also a temporary table (#Periods) with the following list:

Period
201208
201209
201210

The query I need is to give me back the following list:

IDServiceClient | Period
1               | 201209
1               | 201210
2               | 201208
2               | 201209
2               | 201210
3               | 201208
3               | 201209
4               | 201208
4               | 201209
4               | 201210

Which are client services but the ranks of the temporary table, not those who are already inserted

This is what i have:

Table periods:

DECLARE @i int
DECLARE @mm int
DECLARE @yyyy int,
DECLARE @StartDate datetime
DECLARE @EndDate datetime

set @EndDate = (SELECT GETDATE())
set @StartDate = (SELECT DATEADD(MONTH, -3,GETDATE()))

CREATE TABLE #Periods (Period int)

set @i = 0

WHILE @i <= DATEDIFF(MONTH, @StartDate , @EndDate )
BEGIN
    SET @mm= DATEPART(MONTH, DATEADD(MONTH, @i, @FechaInicio))
    SET @yyyy= DATEPART(YEAR, DATEADD(MONTH, @i, @FechaInicio))

    INSERT INTO #Periods (Period) 
        VALUES (CAST(@yyyy as varchar(4)) + RIGHT('00'+CONVERT(varchar(6), @mm), 2))

    SET @i = @i + 1;
END

Relation between ServicesClients and Services:

SELECT s.Name, sc.IDClient FROM Services
    JOIN ServicesClients AS sc
      ON sc.IDService = s.ID

Services already done and when:

SELECT s.Name, scd.Period FROM Services
    JOIN ServicesClients AS sc
      ON sc.IDService = s.ID
    JOIN ServicesClientsDone AS scd
      ON scd.IDServiceClient = sc.IDServiceClient

The question is: How can i do to get the list between services installed on clients and date range without the services already done?

Answer 1

With a left join.

select ServicePeriods.*  
from 
(
    SELECT sc.IDServiceClient, period 
    FROM Services s
    inner join ServicesClients AS sc 
    cross join #periods 
      ON sc.IDService = s.ID 
) ServicePeriods 
    left join 
(
    SELECT scd.IDServiceClient, scd.Period 
    FROM Services s
    INNER JOIN ServicesClients AS sc 
      ON sc.IDService = s.ID 
    INNER JOIN ServicesClientsDone AS scd 
      ON scd.IDServiceClient = sc.IDServiceClient
) exclude
    on ServicePeriods.IDServiceClient = exclude.IDServiceClient  
    and ServicePeriods.Period = exclude.Period 
where exclude.IDServiceClient is null 

Or with an except query

SELECT sc.IDServiceClient, period 
FROM Services s
    INNER JOIN ServicesClients AS sc 
    cross join periods 
      ON sc.IDService = s.ID 

EXCEPT

SELECT scd.IDServiceClient, scd.Period 
FROM Services s
    INNER JOIN ServicesClients AS sc 
      ON sc.IDService = s.ID 
    INNER JOIN ServicesClientsDone AS scd 
      ON scd.IDServiceClient = sc.IDServiceClient