SELECT CustID, COALESCE(CASE WHEN ValidLand = 0 THEN NULL ELSE LandPhone END,

CASE WHEN ValidMobile = 0 THEN NULL ELSE MobilePhone END,

CASE WHEN ValidOffice = 0 THEN NULL ELSE OfficePhone END)...

SELECT CustID, COALESCE(LandPhone, MobilePhone, OfficePhone) AS Phone

FROM PHONENOS

Such insanely bloated calendar tables have actually become much closer to the norm.

It's terrible.  Create a nonwork days table with only the dates in it (you could also add a...

So like I asked before... what would...

While I usually and strongly agree that ISNULL shouldn't be used on table columns in a Join, Where, or other column based criteria matching, "It Depends" is...

While I usually and strongly agree that ISNULL shouldn't be used on table columns in a Join, Where, or other column based criteria matching, "It Depends" is always a...

Still there is a shorter version:

select * 
from leftTable  T1
join rightTable T2 
   on (
     ...

SELECT CONVERT(varchar(10), I.InvoiceDate, 110) AS InvoiceDate

Still there is a shorter version:

select * 
from leftTable  T1
join rightTable T2 
   on (
      T1.C1 =...

You never want to use ISNULL() in a WHERE or JOIN clause.  The code may be slightly longer the other way, but it could potentially run much faster.

ALTER SCHEMA [dbo] TRANSFER HWData.DesktopSoft_Master;

Then your original JOIN is fine and likely the cleanest way to do the join.

So you want a NULL in the column to match *every* column on the other table that isn't NULL?  I.e., NULL is like a wildcard match?

I would think you'd want this:

T1 join T2

on ((T1.C1 = T2.C1) OR (T1.C1 IS NULL AND T2.C1 IS NULL))

and ((T1.C2 = T2.C2) OR (T1.C2 IS NULL AND T2.C2 IS NULL))

How critical is your application?

You will have an outage between steps 2 and 3 and if the table has foreign key constraints you cannot use truncate table

Don't forget to...