SQL {SQL} | R Documentation |
Runs Duckdb SQL statements on in-memory data frames without registering nor copying them. Optionnaly sends the result of a query to a parquet file in an efficient way. Using the 'path' argument may be be twenty times faster than using the COPY ... TO SQL statement.
SQL(query,path)
query |
A character string containing SQL statements undertandable by Duckdb. |
path |
A path to a parquet file to be created. |
If 'path' is not given a value, returns the result of the query as a data frame, else returns an invisible NULL.
SQL("SELECT * FROM mtcars LIMIT 1")
# Temporary tables may be created but must be quoted when used
SQL("
CREATE TABLE cyls AS SELECT DISTINCT cyl FROM mtcars;
SELECT * FROM 'cyls'
")
## Not run:
# Mixing data frames and parquet files, then writing to parquet
dep <- rio::import('V:/PALETTES/IGoR/data/dep2014.dbf')
SQL(
"SELECT a.*,b.REGION
FROM 'V:/PALETTES/parquet/rp68a19.parquet' a
LEFT JOIN dep b
ON a.DR=b.DEP",
'V:/PALETTES/tmp/rp68a19s.parquet'
)
## End(Not run)