How to do it…

1. Let's create an S3 bucket for our data. Go to S3 and click on Create new bucket. Type the name cookbook-spectrum.
2. Now, we can unload data into this bucket and run this command, as shown in the following code block:

unload ('select * from lineorder')
to 's3://cookbook-spectrum/
iam_role 'arn:aws:iam::615381814665:role/RedshiftS3Access'
delimiter '\t'

3. Let's create the external schema, as follows:

create external schema datalake 
from data catalog 
database 'spectrumdb' 
iam_role 'arn:aws:iam::615381814665:role/RedshiftS3Access'
create external database if not exists;

4. Let's create an external table in this schema, as follows:

create external table datalake.lineorder
(
  lo_orderkey INTEGER 
  ,lo_linenumber INTEGER
  ,lo_custkey INTEGER
  ,lo_partkey INTEGER
  ,lo_suppkey INTEGER
  ,lo_orderdate INTEGER
  ,lo_orderpriority VARCHAR(15)
  ,lo_shippriority VARCHAR(1)
  ,lo_quantity INTEGER 
  ,lo_extendedprice INTEGER
  ,lo_ordertotalprice INTEGER 
  ,lo_discount INTEGER 
  ,lo_revenue INTEGER
  ,lo_supplycost INTEGER 
  ,lo_tax INTEGER 
  ,lo_commitdate INTEGER
  ,lo_shipmode VARCHAR(10)
)
row format delimited
fields terminated by '\t'
stored as textfile
location 's3://cookbook-spectrum/
table properties ('numRows'='172000');

5. We can test this table by running queries against it, such as SELECT * FROM datalake.lineorder, or we can adjust our Tableau Data Source and use a Spectrum table instead of the initial one. However, it is better to tune the external table before use, otherwise Spectrum will scan the full table.