R accessing DB query results by column and row number

Answer 1

Try this:

# I'd avoid new as a variable name
newdata <- sqlQuery(newconn,"SELECT COL1, COL2 FROM TABLE1;", errors = TRUE, 1)

# index data frame by row number and column name

if (newdata[3, "COL1"] == "someValue") {
     print("found someValue")
} else {
     print ("failed")
}

You can also do

if (newdata[3, 2] == "MYSTRING")

to index by row and column index.

Lastly, testing for NA is different than string comparison -- you need is.null() or is.na() as this may get converted by the ODBC access.