upsert {
query {
q(func: eq(email, "user@company1.io")) {
v as uid
}
}
mutation {
set {
uid(v) <age> "28" .
}
}
in this example, the age
will be updated no matter it already has a old value or not. how to value only if the value is not exist? such as uid(v) <age> val(age) || 28