I am moving the data from MongoDB to BIgquery and all the nested columns are there in the raw table but the final table the values are null .I tried this same in the month of December at that time the json objects were coming in the string format but now it is coming blank . I figured out the json values which are of structure type are getting captured by the json_extract function and not by json_extract_scalar function.How can i change the json_extract_scalar by json_extract in the code ?using mongoDB version- 0.1.13