Redshift: paste() and paste0() translations

Fixes #458
tidyverse · Sep 22, 2020 · 175af9c · 175af9c
1 parent 54ea038
commit 175af9c
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diff --git a/NEWS.md b/NEWS.md
@@ -3,6 +3,8 @@
 * New RedShift translations when used with `RPostgres::Redshift()`.
   * `str_replace()` errors since there's no Redshift translation, 
      and `str_replace_all()` uses `REGEXP_REPLACE()` (#446).
+
+  * `paste()` and `paste0()` use `||` (#458).
 
 * `sql_translate_env.Microsoft SQL Server()` now uses `sql_try_cast()` instead
   of `sql_cast()` for MSSQL version 11+ (2012+) (@DavidPatShuiFong, #380).

diff --git a/R/backend-redshift.R b/R/backend-redshift.R
@@ -4,6 +4,12 @@ sql_translate_env.RedshiftConnection <- function(con) {
 
   sql_variant(
     sql_translator(.parent = postgres$scalar,
+
+      # https://stackoverflow.com/questions/56708136
+      paste  = sql_paste_redshift(" "),
+      paste0 = sql_paste_redshift(""),
+      str_c = sql_paste_redshift(""),
+
       # https://docs.aws.amazon.com/redshift/latest/dg/REGEXP_REPLACE.html
       str_replace = sql_not_supported("str_replace"),
       str_replace_all = function(string, pattern, replacement) {
@@ -17,3 +23,7 @@ sql_translate_env.RedshiftConnection <- function(con) {
 
 #' @export
 sql_translate_env.Redshift <- sql_translate_env.RedshiftConnection
+
+sql_paste_redshift <- function(sep) {
+  sql_paste_infix(sep, "||", function(x) sql_expr(cast(!!x %as% text)))
+}
diff --git a/tests/testthat/test-backend-redshift.R b/tests/testthat/test-backend-redshift.R
@@ -8,4 +8,8 @@ test_that("string translations", {
 
   expect_error(translate_sql(str_replace("xx", ".", "a")), "not available")
   expect_equal(translate_sql(str_replace_all("xx", ".", "a")), sql("REGEXP_REPLACE('xx', '.', 'a')"))
+
+  expect_equal(translate_sql(paste("x", "y")), sql("'x' || ' ' || 'y'"))
+  expect_equal(translate_sql(paste0("x", "y")), sql("'x' || 'y'"))
+  expect_equal(translate_sql(str_c("x", "y")), sql("'x' || 'y'"))
 })