how to use right/left to split a variable in sqldf, as in left(x,n)

问题

Is there a different function in R to use to get the same result as in SQL for left or right function?

For instance, the following query in SQL would give the first 6 characters of a column:

select left(x, 6)
from table

However, when I try this in sqldf like this:

sqldf("select left(x,6) from table")

I get the following error:

Error in sqliteSendQuery(con, statement, bind.data) :

error in statement: near "(": syntax error

It gives me the x variable but not left(x,6). To clarify, the length of x is more than 6.

回答1:

In sqldf, the function is named leftstr, not left. (answer by G.Grothendieck in the comment)

来源：https://stackoverflow.com/questions/31843373/how-to-use-right-left-to-split-a-variable-in-sqldf-as-in-leftx-n