Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_20 (code__iata_ VARCHAR, total_cargo__metric_tonnes_ VARCHAR)

### Question ###
What is the IATA code of the airport that has a Total Cargo of 1,838,894 Metric Tonnes?

### Accurate SQL ###

SELECT code__iata_ FROM table_name_20 WHERE total_cargo__metric_tonnes_ = "1,838,894"