The structure of the two schemas (one with all the fields, and one with just the First Name and Age fields) must be compatible. The SchemaMatch function compares CLOBs or JSON types representing an Avro schema for compatibility, and can confirm ahead of time whether the schemas are compatible.
The resulting Avro instance is composed of the new schema with the fields (First Name and Age, in the example) and the projected binary-encoded Avro value. If the values for the Avro instance or the new schema are NULL, the result is NULL.
If the new schema is invalid or incompatible with the original schema, an error occurs.