Skip to content

Floor built in function return type  #8795

Closed
Closed
Floor built in function return type #8795

Description

@Ted-Jiang
Ted-Jiang
opened on Jan 9, 2024

https://github.com/apache/arrow-datafusion/blob/f0af5eb949e2c5fa9f66eb6f6a9fcdf8f7389c9d/datafusion/expr/src/built_in_function.rs#L899-L915

from this code floor() only retun float type

but from postgresql

floor ( numeric ) → numeric

floor ( double precision ) → double precision

Nearest integer less than or equal to argument

floor(42.8) → 42

floor(-42.8) → -43

https://www.postgresql.org/docs/current/functions-math.html

Activity

  1. Ted-Jiang commented on Jan 9, 2024

    @Ted-Jiang
    Ted-Jiang
    on Jan 9, 2024
    MemberAuthor

    seems cast in some place

    ❯ explain verbose  select floor(-1);
+------------------------------------------------------------+--------------------------------------------------------------------------------------------------------+
| plan_type                                                  | plan                                                                                                   |
+------------------------------------------------------------+--------------------------------------------------------------------------------------------------------+
| initial_logical_plan                                       | Projection: floor(Int64(-1))                                                                           |
|                                                            |   EmptyRelation                                                                                        |
| logical_plan after inline_table_scan                       | SAME TEXT AS ABOVE                                                                                     |
| logical_plan after type_coercion                           | Projection: floor(CAST(Int64(-1) AS Float64))                                                          |
|                                                            |   EmptyRelation                                                                                        |
| logical_plan after count_wildcard_rule                     | SAME TEXT AS ABOVE                                                                                     |
| analyzed_logical_plan                                      | SAME TEXT AS ABOVE                                                                                     |
| logical_plan after eliminate_nested_union                  | SAME TEXT AS ABOVE                                                                                     |
| logical_plan after simplify_expressions                    | Projection: Float64(-1) AS floor(Int64(-1))                                                            |
|                                                            |   EmptyRelation                                                                                        |
| logical_plan after unwrap_cast_in_comparison               | SAME TEXT AS ABOVE                                                                                     |
| logical_plan after replace_distinct_aggregate              | SAME TEXT AS ABOVE                                                                                     |
| logical_plan after eliminate_join                          | SAME TEXT AS ABOVE

  2. alamb commented on Jan 9, 2024

    @alamb
    alamb
    on Jan 9, 2024
    Contributor

    If you are saying that floor(decimal) should return decimal that makes sense to me

  3. maruschin commented on Jan 10, 2024

    @maruschin
    maruschin
    on Jan 10, 2024
    Contributor

    @alamb, @Ted-Jiang, hi! I created draft PR

    if the idea is ok, would like to compare all return types in pg and fixed them

  4. Ted-Jiang commented on Jan 10, 2024

    @Ted-Jiang
    Ted-Jiang
    on Jan 10, 2024
    MemberAuthor

    If you are saying that floor(decimal) should return decimal that makes sense to me

    Yes, basiclly all numeric type should have the return type same as input.
    And i have check the numeric type list is same as pg.

  5. theirix commented on Feb 15, 2026

    @theirix
    theirix
    on Feb 15, 2026
    Contributor

    The floor and ceil udfs now support decimal return type via #18979.

    Non-trivial functions like pow, log, etc. are also supported (linked in the parent EPIC).

    So I think this issue is fixed and could be closed

  6. Jefffrey commented on Feb 18, 2026

    @Jefffrey
    Jefffrey
    on Feb 18, 2026
    Contributor

    Looks like we're consistent with integers too:

    psql (18.2 (Debian 18.2-1.pgdg13+1))
Type "help" for help.

postgres=# select pg_typeof(1);
 pg_typeof
-----------
 integer
(1 row)

postgres=# select pg_typeof(floor(1));
    pg_typeof
------------------
 double precision
(1 row)

    DF:

    DataFusion CLI v52.1.0
> select floor(1);
+-----------------+
| floor(Int64(1)) |
+-----------------+
| 1.0             |
+-----------------+
1 row(s) fetched.
Elapsed 0.059 seconds.

> select arrow_typeof(floor(1));
+-------------------------------+
| arrow_typeof(floor(Int64(1))) |
+-------------------------------+
| Float64                       |
+-------------------------------+
1 row(s) fetched.
Elapsed 0.008 seconds.

    Thanks for checking @theirix

  7. Jefffrey
    closed this as completedon Feb 18, 2026
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions