Back to Code Snippets
Ryan Boyd
@ryan-1
Select a sample of rows from a tableSQL
DuckDB allows sampling of data in your tables using a several different statistical techniques, usually to increase performance. The default sampling method is used in this case- this is a bernoulli variant where each vector has a specified chance of being included in the result set.
Execute this SQL
-- uses system sampling to select 10% of the people rows SELECT * FROM people USING SAMPLE 10%;Copy code
Ryan Boyd
Expand
Share link
Select all columns except a fewSQL
Editor's note: tired of copying/pasting many column names to select all columns except a handful? The EXCLUDE() function allows you to exclude specific columns from the result set. Together with COLUMNS() and REPLACE() it provides an easy way to specific the data you want returned.
Execute this SQL
SELECT * EXCLUDE (column1, colum2) FROM ducks;Copy code
Ryan Boyd
Expand
Share link
Download CSV and convert to ParquetSQL
Execute this SQL
COPY (SELECT * FROM read_csv_auto( 'http://raw.githubusercontent.com/fivethirtyeight/data/master/bechdel/movies.csv')) TO 'movies.parquet' (FORMAT 'parquet');Copy code
Ryan Boyd
Copy code
Expand
Share link