A small reprex. The problem exist in Rstudio 1.4 but not in 1.3
```{r}
library(tidyverse)
library(DBI)
```{r}
mydb <- dbConnect(RSQLite::SQLite(), "")
testdb <- tribble(~variable_name_normal, ~variable_name_spec_ø,
'value', 'value',
'æøå', 'æøå')
dbWriteTable(mydb, 'test_table', testdb, overwrite = TRUE)
```{sql, connection='mydb', output.var='local_file'}
select
variable_name_normal,
variable_name_spec_ø
from test_table
On Windows 7 prof and Windows 10 (both with Danish std. codepage) I get this error msg:
Fejl: no such column: variable_name_spec_ø
Failed to execute SQL chunk
"ø" is rendered as "ø"
On my Mac - it works flawless, as it used to do on Windows in version 1.3
Hope this will do as a valid reprex 
Brgds. Henrik