Append
Concatenates two tables together.
Equivalent to UNION ALL
in SQL. The number of rows is always the sum of the
number of rows from the two input tables. To replicate UNION DISTINCT
, see
set operations.
PRQL
from employees_1
append employees_2
SQL
SELECT
*
FROM
employees_1
UNION
ALL
SELECT
*
FROM
employees_2
Remove
experimental
Removes rows that appear in another relation, like EXCEPT ALL
. Duplicate rows
are removed one-for-one.
PRQL
from employees_1
remove employees_2
SQL
SELECT
*
FROM
employees_1 AS t
EXCEPT
ALL
SELECT
*
FROM
employees_2 AS b
Intersection
experimental
PRQL
from employees_1
intersect employees_2
SQL
SELECT
*
FROM
employees_1 AS t
INTERSECT
ALL
SELECT
*
FROM
employees_2 AS b
Set operations
experimental
To imitate set operations i.e. (UNION
, EXCEPT
and INTERSECT
), you can use
the following functions:
let distinct = rel -> (from t = _param.rel | group {t.*} (take 1))
let union = `default_db.bottom` top -> (top | append bottom | distinct)
let except = `default_db.bottom` top -> (top | distinct | remove bottom)
let intersect_distinct = `default_db.bottom` top -> (top | intersect bottom | distinct)
Don’t mind the default_db.
and noop
, these are compiler implementation
detail for now.