dplyr_join_0.6.0.R

library(dplyr)

con <- DBI::dbConnect(RSQLite::SQLite(), ":memory:")
DBI::dbWriteTable(con, "mtcars", mtcars)

mtcars2 <- tbl(con, "mtcars")
mtcars2

mtcars2 %>%
  select(cyl) %>%
  head(3) %>%
  show_query()
#> <SQL>
#>   SELECT `cyl` AS `cyl`
#> FROM `mtcars`
#> LIMIT 3

inner_join(mtcars2, mtcars2, by = "cyl") %>%
  show_query()
#> <SQL>
#>   SELECT `TBL_LEFT`.`mpg` AS `mpg.x`, `TBL_LEFT`.`cyl` AS `cyl`, `TBL_LEFT`.`disp` AS `disp.x`, `TBL_LEFT`.`hp` AS `hp.x`, `TBL_LEFT`.`drat` AS `drat.x`, `TBL_LEFT`.`wt` AS `wt.x`, `TBL_LEFT`.`qsec` AS `qsec.x`, `TBL_LEFT`.`vs` AS `vs.x`, `TBL_LEFT`.`am` AS `am.x`, `TBL_LEFT`.`gear` AS `gear.x`, `TBL_LEFT`.`carb` AS `carb.x`, `TBL_RIGHT`.`mpg` AS `mpg.y`, `TBL_RIGHT`.`disp` AS `disp.y`, `TBL_RIGHT`.`hp` AS `hp.y`, `TBL_RIGHT`.`drat` AS `drat.y`, `TBL_RIGHT`.`wt` AS `wt.y`, `TBL_RIGHT`.`qsec` AS `qsec.y`, `TBL_RIGHT`.`vs` AS `vs.y`, `TBL_RIGHT`.`am` AS `am.y`, `TBL_RIGHT`.`gear` AS `gear.y`, `TBL_RIGHT`.`carb` AS `carb.y`
#> FROM `mtcars` AS `TBL_LEFT`
#> INNER JOIN `mtcars` AS `TBL_RIGHT`
#> ON (`TBL_LEFT`.`cyl` = `TBL_RIGHT`.`cyl`)