matching all nulls agianst another table

Please start any new threads on our new site at https://forums.sqlteam.com. We've got lots of great SQL Server experts to answer whatever question you can come up with.

All Forums

SQL Server 2008 Forums

Transact-SQL (2008)

matching all nulls agianst another table

Author

Topic

jszulc
Yak Posting Veteran

66 Posts

Posted - 2012-03-02 : 08:00:05

How can I build a query to show all records from vm_sites with site column populated based on matches from Assets table? The number of records in vm_Sites should be still the same after the match, just trying to match all nulls in vm_Sites with Assets table.

Table 1
SELECT Sname,site,volsize from vm_Sites

Table 2
SELECT Sname,site from Assets

Thank you

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2012-03-02 : 12:33:00

you cant match NULLs as NULL cant be equated to NULL under default conditions. NULL means its unknown value and its not a value by itself. So comparison between two NULL doesnt even make sense

if for matching actual values you can use below logic


SELECT *
FROM vm_sites v
WHERE EXISTS (SELECT 1 FROM Assests WHERE site = v.site

and if you really think all NULL in your case have to be treated equivalent use ISNULL or COALESCE functions to change them to valid default value before comparison

------------------------------------------------------------------------------------------------------
SQL Server MVP
http://visakhm.blogspot.com/

Subscribe to SQLTeam.com

SQLTeam.com Articles via RSS

SQLTeam.com Weblog via RSS

- Advertisement -

Resources