Querying Data
After Connecting, you can execute a SQL statement and retrieve the results.
SELECT Procedure
You can use the sqlQuery function to execute queries. By default, it will return all the results as a single data frame. This works well for smaller result sets.
results <- sqlQuery(cnx, "SELECT SMVendorID, Category FROM Vendors WHERE SMVendorID = 'S123456'") for (row in 1:nrow(results)) { cat(paste("SMVendorID = ", results[row,]$SMVendorID, "\n")) cat(paste("Category = ", results[row,]$Category, "\n")) }
Iterating over the Results
For larger result sets, sqlQuery can return results in batches instead of storing the entire result set in memory. When there are no results left, or an error occurs, sqlQuery and sqlGetResults will return an integer error code instead of a data frame.
results <- sqlQuery(cnx, "SELECT SMVendorID, Category FROM Vendors WHERE SMVendorID = 'S123456'", max = 1000) while (is.data.frame(results)) { for (row in 1:nrow(results)) { cat(paste("SMVendorID = ", results[row,]$SMVendorID)) cat(paste("Category = ", results[row,]$Category)) } rows <- sqlGetResults(cnx, max = 1000) }