Question

Till today my thoughts about the inner join were it will return the minimum number of rows that exist in tables satisfying a joining condition.

Ex. if table A contains 4 rows and table B contains 7 rows . i was expecting that 4 rows can be the maximum output if they satisfy the joining condition.

I just wrote an sp in which i was creating two temporary tables and was populating them. then i took an inner join of them but returning more rows (In my case 29 rows were returned i was expecting 4)
After some search i found this
link

which confirms that i can happen but i still wonder what are my options to limit the returned result.

Below is my stored procedure.

ALTER PROCEDURE [dbo].[GetDDFDetailOnSiteCol]
@siteId int,
@colNum int
AS
BEGIN
SET NOCOUNT ON;

create Table #portDetail
(
ddfId int,
portDetail nvarchar(50),
siteId int
)
Insert into #portDetail SELECT  ddf.id,  ddf.portDetail, site.Site_ID  from site
        inner join ddf ON site.Site_ID = ddf.siteCodeID 
        where ddf.siteCodeID = @siteId and ddf.colNo= @colNum
        order by colNo,blockNum,portRowNum,portColNum

create Table #portAllocationDetail
(
assigned_slot nvarchar(50),
siteId int
)
Insert into #portAllocationDetail 
SELECT  dbo.portList.assigned_slot, dbo.site.Site_ID
FROM dbo.portList INNER JOIN
 dbo.site ON dbo.portList.siteCodeID = dbo.site.Site_ID
 where dbo.site.Site_ID = @siteId

--select * from #portAllocationDetail   
Select #portDetail.ddfId,#portDetail.portDetail,#portAllocationDetail.siteId,#portAllocationDetail.assigned_slot FROM #portDetail 
INNER JOIN #portAllocationDetail 
ON
#portDetail.siteId = #portAllocationDetail.siteId
END

Answer 1

An inner join repeats each matching row in TableB for each row in TableA. So if there are 4 rows in TableA, and 7 in TableB, the maximum rowcount is 28.

Example at SQL Fiddle.