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

Answer 2

This error generally occurs when the syntax of DDL has some silly errors.There are several answers that explain different errors based on there state.The simple solution to this problem is to patiently look into DDL and verify following points line by line:-

1. Check for missing commas
2. Unbalanced `(backtick operator)
3. Incompatible datatype not supported by HIVE(HIVE DATA TYPES REFERENCE)
4. Unbalanced comma
5. Hypen in table name

Answer 3

Unfortunately, at the moment the syntax validation error messages are not very descriptive in Athena, this error may mean "almost" any possible syntax errors on the create table statement.

Although this is annoying at the moment you will need to check if the syntax follows the Create table documentation

Some examples are:

• Backticks not in place (as already pointed out)
• Missing/extra commas (remember that the last column doesn't need the comma after column definition
• Missing spaces
• More ..

Answer 4

In my case, I was missing the singlequotes for the S3 URL

Answer 5

In my case, it was that one of the table column names was enclosed in single quotes, as per the AWS documentation :( ('bucket')

Answer 6

Something that wasn't obvious for me the first time I used the UI is that if you get an error in the create table 'wizard', you can then cancel and there should be the query used that failed written in a new query window, for you to edit and fix.

My database had a hypen, so I added backticks in the query and rerun it.