backend-hana.md
In dbplyr: A 'dplyr' Back End for Databases

custom string translations

Code
  test_translate_sql(paste0("a", "b"))
Output
  <SQL> 'a' || 'b'

Code
  test_translate_sql(paste("a", "b"))
Output
  <SQL> 'a' || ' ' || 'b'

Code
  test_translate_sql(substr(x, 2, 4))
Output
  <SQL> SUBSTRING(`x`, 2, 3)

Code
  test_translate_sql(substring(x, 2, 4))
Output
  <SQL> SUBSTRING(`x`, 2, 3)

Code
  test_translate_sql(str_sub(x, 2, -2))
Output
  <SQL> SUBSTRING(`x`, 2, LENGTH(`x`) - 2)

copy_inline uses UNION ALL

Code
  copy_inline(con, y %>% slice(0)) %>% remote_query()
Output
  <SQL> SELECT CAST(NULL AS INTEGER) AS `id`, CAST(NULL AS VARCHAR) AS `arr`
  FROM `DUMMY`
  WHERE (0 = 1)
Code
  copy_inline(con, y) %>% remote_query()
Output
  <SQL> SELECT CAST(`id` AS INTEGER) AS `id`, CAST(`arr` AS VARCHAR) AS `arr`
  FROM (
    SELECT NULL AS `id`, NULL AS `arr`
    FROM `DUMMY`
    WHERE (0 = 1)

    UNION ALL

    SELECT 1, '{1,2,3}' FROM DUMMY
  ) AS `values_table`
Code
  copy_inline(con, y %>% slice(0), types = types) %>% remote_query()
Output
  <SQL> SELECT CAST(NULL AS bigint) AS `id`, CAST(NULL AS integer[]) AS `arr`
  FROM `DUMMY`
  WHERE (0 = 1)
Code
  copy_inline(con, y, types = types) %>% remote_query()
Output
  <SQL> SELECT CAST(`id` AS bigint) AS `id`, CAST(`arr` AS integer[]) AS `arr`
  FROM (
    SELECT NULL AS `id`, NULL AS `arr`
    FROM `DUMMY`
    WHERE (0 = 1)

    UNION ALL

    SELECT 1, '{1,2,3}' FROM DUMMY
  ) AS `values_table`