What is difference between null and empty in sql server

Have a read of this Wiki Null(SQL)[^].

But basically NULL does not hold a value, where '' (with no spaces) is a value.

HI,

It is vary important part of the sql at the time of insertion, Depends on datatype of column.
If you pass the empty value it assign default value of that datatype as datetime column saved by default value -- " 1900-01-01 00:00:00.000 ".
So this is not favorable condition - so using asp.net your can insert DbNull value to database. Then it contain Null value(Not assign yet).

It is all depends on conditions which we required-- null or empty

Thanks
Asp.Net & C# Blog[^]

NULL                          EmptyString
-----------------------------------------------------------
1. No datatype                   could belong to char/varchar,nvarchar,nchar etc ...datatype
2. occupy 1 bit per column       Occupy 0 bytes
   for each row to state 
   it's NULL 

Happy Coding!
:)

SELECT Something FROM Data
WHERE Something = NULL 

Always return false with = !!!

SELECT Something from Data 
WHERE Something IS NULL

the value of NULL isn't equal to NULL:

SELECT Something FROM Data
WHERE NULL = NULL OR NULL IS NULL

return FALSE!

With String '' you can use =, but better use IS, IS NOT