Add tested R query how-to and correct usage examples

README.md

@@ -46,6 +46,23 @@ WHERE program_year = 2024
 GROUP BY 1 ORDER BY 2 DESC LIMIT 10;
 ```
 
+### R with DBI and duckdb
+
+Install the dependencies once with `install.packages(c("DBI", "duckdb"))`.
+
+```r
+library(DBI)
+con <- dbConnect(duckdb::duckdb())
+dbExecute(con, "INSTALL httpfs")
+dbExecute(con, "LOAD httpfs")
+dbExecute(con, "ATTACH 'https://huggingface.co/datasets/Nason/openpayments-database/resolve/main/openpayments.duckdb' AS op (READ_ONLY)")
+dbGetQuery(con, "SELECT program_year FROM op.general_payments LIMIT 5")
+dbDisconnect(con, shutdown = TRUE)
+```
+
+DuckDB uses HTTP range requests; queries run on your machine and may need substantial memory or download data. A `LIMIT` does not guarantee a small scan.
+
+
 Joins to the `cms-medicare` datapond database on NPI — see the GitHub README
 for the worked Open Payments x Medicare utilization example and measured
 join rates.