In Scotland, people used to use
Sandy as the short form or nickname form of
Alexander, and for centuries
Sandy was the routine nickname for a Scotsman. Now they mostly get called Mac! But I know an
Alexander who is known as
Sandy, so it still happens.
Sandra was very popular for girls from about 1940 to 1960; now people mostly choose
Alexa instead.
Is
Sandro your full name, or are you
Alessandro with
Sandro as a nickname?