Amazon Athena: no viable alternative at input

Question

While creating a table in Athena; it gives me following exception:

no viable alternative at input

Answer 1

As other users have noted, the standard syntax validation error message that Athena provides is not particularly helpful. Thoroughly checking the required DDL syntax (see HIVE data types reference) that other users have mentioned can be pretty tedious since it is fairly extensive.

So, an additional troubleshooting trick is to let AWS's own data parsing engine (AWS Glue) give you a hint about where your DDL may be off. The idea here is to let AWS Glue parse the data using its own internal rules and then show you where you may have made your mistake.

Specifically, here are the steps that worked for me to troubleshoot my DDL statement, which was giving me lots of trouble:

1. create a data crawler in AWS Glue; AWS and lots of other places go through the very detailed steps this requires so I won't repeat it here
2. point the crawler to the same data that you wanted (but failed) to upload into Athena
3. set the crawler output to a table (in an Athena database you've already created)
4. run the crawler and wait for the table with populated data to be created
5. find the newly-created table in the Athena Query Editor tab, click on the three vertical dots (...), and select "Generate Create Table DLL":
6. this will make Athena create the DLL for this table that is guaranteed to be valid (since the table was already created using that DLL)
7. take a look at this DLL and see if/where/how it differs from the DLL that you originally wrote. Naturally, this automatically-generated DLL will not have the exact choices for the data types that you may find useful, but at least you will know that it is 100% valid
8. finally, update your DLL based on this new Glue/Athena-generated-DLL, adjusting the column/field names and data types for your particular use case