Null & Zero in SQL Server

Question

Hi.. I'm very confusion in zero and null value in SQL SERVER ? Please explain null and zero value with an example ? Thanks.....

Pravin Ghadge · Answer

Hi Zero is a value which is exist in the database. Null is a special marker used in Sql to indicate that a data value does not exist in the database For Eg: ColumnName Datatype BirthDate Datetime BirthDate column can have null value but can't contain zero value.

Aarti · Answer

Hi Vineet A value of NULL indicates that the value is unknown. A value of NULL is different from an empty or zero value. No two null values are equal. Comparisons between two null values or between a NULL and any other value return unknown because the value of each NULL is unknown. create table test_null ( tid int identity(11) t_val varchar(20)) ; go insert into test_null(t_val) values(default) go 20 select * from test_null where t_val = null go --You will not get any output coz Ansi null is ON SET ANSI_NULLS Off select * from test_null where t_val = null --Now you'll get all Null Values.

Vineet Kumar Saini · Answer

Thanks Aarti.....