sql - DATALENGTH() or ISNULL() to retrieve fields that are not null and not empty -

quite simply, of following methods better in where clause retrieve records field_name not null , not empty

where datalength(field_name) > 0 

or

where isnull(field_name, '') <> '' 

update

i have been informed first method gives spurious results types of fields... agree?

firstly,

select * table column <> '' 

will give same results as

select * table isnull(column, '') <> '' 

because records condition unknown rather false still filtered out. go first option.

datalength counts trailing spaces, comparison '' not. whether want ' ' compare unequal ''. if do, need datalength. if don't, compare ''.

note text/ntext types, comparisons not supported, datalength is.