Pretty print sql code from separate file with knitr

问题

Knitr produces a nice, syntax highlighted code when using a code chunk as below.

```sql
SELECT column
FROM table
```

Is it possible to achieve the same thing but with the sql code stored in a file? Something like:

```sql
read_chunk('mycode.sql')
```

回答1:

I think you can use an inline R expression to achieve it:

```sql
`r xfun::file_string('mycode.sql')`
```

来源：https://stackoverflow.com/questions/24524594/pretty-print-sql-code-from-separate-file-with-knitr