Baoqi Wu

Support IN set of values

4

Currently, seems the only supported "in" is like: ``` from employees filter (age | in 20..80) ``` which will be translated to: ``` SELECT employees.* FROM employees WHERE age BETWEEN...

`include` other prql files & module system

5

Currently, seems we only have 1 [stdlib.prql](https://github.com/prql/prql/blob/main/prql-compiler/src/sql/stdlib.prql) which will be included when parse every other prql file. maybe we can make this "include" as a feature. so, I can define...