-- This selects only specific fields from the CSV
-- It also renames one of the fields in the target schema
COPY (SELECT col1, col2, col3 AS new_col_name
	    FROM read_csv('~/data/source.csv',AUTO_DETECT=TRUE))
  TO '~/data/target.parquet' (FORMAT 'PARQUET', CODEC 'ZSTD');
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LOAD spatial;

-- Pick for example any Garmin Connect or Strava export as GPX file
-- https://en.wikipedia.org/wiki/GPS_Exchange_Format

SELECT round(
         -- Compute the length of the geomentry in the units of the
         -- reference system being used
         ST_Length(
           -- Transform from standard GPS WGS-84 into a reference system 
           -- that uses meters. EPSG:25832 stands for ETRS89 / UTM zone 32N,
           -- Europe between 6°E and 12°E
           ST_transform(
             -- Fix the order of coordinates 
             -- (GXP read as long/lat, we need lat/long)
             ST_FlipCoordinates(
               -- Turn the WKT into a DuckDB Geometry
               ST_GeomFromWKB(wkb_geometry)
             ),
            'EPSG:4326',
            'EPSG:25832'
           )
       ) /1000, 2) AS 'Distance (km)'
FROM st_read('activity_11501782487.gpx', layer='tracks');
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-- listing files
FROM glob('dataset/*');

-- reading from files
FROM 'dataset/*.parquet' LIMIT 100; 

-- reading parquet files metadata (min_value, max_value, null_count for each field in each file)
FROM parquet_metadata('dataset/*.parquet');

-- convert files or export tables to parquet
COPY (FROM tbl) TO 'file.parquet' (FORMAT 'parquet');
COPY 'data.csv' TO 'data.paruqet' (FORMAT 'parquet');
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-- Here we make use of list_transform and 
-- the fact that DuckDB knows lambda expressions
SELECT list_transform(split('01:08:22', ':'), x -> CAST (x AS INTEGER));
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with bits as (
    select
    -- add 8 bits to the end to account for the delimiter
    bit_length(columns(*))  + 8
    from <TABLE>
),
-- aggregate all columns
bits_agg as (
    select sum(columns(*)) from bits
),
-- unpivot a wide single row of aggs to single column
bits_col as (
    unpivot bits_agg on columns(*)
)
-- add them all up & convert to mb
select sum(value) / (8 * 1024 ** 2) as mb
from bits_col
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-- Using  Scaleway as an example, where first 75GB is free
-- https://www.scaleway.com/en/object-storage/
-- This also works for Google Storage, Digital Ocean Spaces, 
-- Wasabi and so on

-- set these like you do for AWS
SET s3_access_key_id='MY_KEY'
SET s3_secret_access_key='MY_SECRET'

-- set the endpoint and region to override the default of 
-- using AWS endpoints
SET s3_endpoint='s3.nl-ams.scw.cloud'
SET s3_region="nl-ams"

SELECT
  -- format a large number with helpful commas 
  -- for readability
  format('{:,}', count(*)) as "total rows in file" 
FROM "s3://<BUCKET_NAME>/<FILE_NAME>.zst.parquet"
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