C# .NET - sql query

 difference betweeen left outer join and left inner join

Hi Sankar

Left Outer Join
-----------------------
Even if both table does not have any common data it will still return all the data from left table,unlike Left join,so it means that left outer join will return all the rows that an inner join returns plus one row for each of the other rows in the first table that did not have a match in the second table

Left Inner Join
-----------------------
There is nothing like Left Inner Join,it is always Inner Join,so if you specified Inner Join,it will be still get only common data between the tables

let me know
thxs

INNER JOIN DISPLAYS ONLY THE RECORDS WHICH ARE SATISFYING
THE JOINING CONDITION,WHERE AS IN AN OUTER JOIN IT DISPLAYS
THE RECORDS WHICH ARE SATISFYING THE CONDITION AND ALSO
WHICH ARE NOT SATIFYING THE CONDITION ALSO.
check here for more info with an example of what i said above
http://www.allinterview.com/showanswers/59061.html

simply speaking inner join fetches the record if there is a match between two tables
and left outer join will fetches the record for every row  in  the left side table .. if there is no data in fetching column it will return as NULL
example :
Admission and Patient
both are having common ID PatientID
select admissiondate,PatientName
 from admission
left outer join Patient on Admission.PatientID=Patient.PatientID
where admissiondate = '2026-08-02'
The above query will fetch the list of all patient names who are all admitted today
admissiondate patientname
2010-08-02     X
null           Y

The null value represents there is no record for patient Y in admission table
but the row will be fetched since it is left outer join query
this row will not be fetched if it is nner join query
Hope this helps.

A left outer join will return all the rows that an inner join returns plus one row for each of the other rows in the first table that did not have a match in the second table.

http://riteshshah.wordpress.com/2009/03/08/complete-ref-of-sql-server-join-inner-join-left-outer-join-right-outer-join-full-outer-join-in-sql-server-2005/