Need to add new function - schema_of_json(). The function should infer schema of JSON string literal. The result of the function is a schema in DDL format.
One of the use cases is passing output of schema_of_json() to from_json(). Currently, the from_json() function requires a schema as a mandatory argument. An user has to pass a schema as string literal in SQL. The new function should allow schema inferring from an example. Let's say json_col is a column containing JSON string with the same schema. It should be possible to pass a JSON string with the same schema to schema_of_json() which infers schema for the particular example.