What's the difference between and ?

Question

do you know if there\'s a difference between these tags on XML/XSD?

 and 

e.g:

<

Answer 1

is the equivalent of an empty string and will render valid against xsd:string, but not against types like xsd:date, xsd:datetime, xsd:decimal etc.

is the equilalent of null and will render valid for all elements which have nillable="true" in the schema-definition