title: Unable to import s3 data to RDS(Postgresql) using aws_commons extension
body: <p>I am trying to import s3 file(CSV file) to Postgre sql rds instance.
  I am running s3 import queries from rds instance as per AWS docs but i am getting below error</p>
  
  <p>ERROR:  syntax error at or near ":"
  LINE 5:    :'s3_uri',
             ^
  SQL state: 42601
  Character: 76</p>
  
  <p>Query i used for downloading s3 file is below:</p>
  
  <p>SELECT aws_s3.table_import_from_s3(
     't1',
     '', 
     '(format csv)',
     :'s3_uri',
  );</p>
  
  <p>Running query as per AWS doc: <a href="https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/PostgreSQL.Procedural.Importing.html#USER_PostgreSQL.S3Import.Overview" rel="nofollow noreferrer">https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/PostgreSQL.Procedural.Importing.html#USER_PostgreSQL.S3Import.Overview</a></p>
  
  <p>SELECT aws_s3.table_import_from_s3(
     't1',
     '', 
     '(format csv)',
     :'s3_uri',
  );</p>