[arrow-datafusion] branch main updated: infer column nullability on joins (#6060)

[alamb]

This is an automated email from the ASF dual-hosted git repository.

alamb pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/arrow-datafusion.git


The following commit(s) were added to refs/heads/main by this push:
     new 560ad35361 infer column nullability on joins (#6060)
560ad35361 is described below

commit 560ad353619f4526352fd3f64d09a59babe87a3c
Author: comphead <comph...@users.noreply.github.com>
AuthorDate: Fri Apr 21 12:15:52 2023 -0700

    infer column nullability on joins (#6060)
---
 .../core/tests/sqllogictests/test_files/join.slt   | 25 ++++++++++++++++-
 datafusion/expr/src/logical_plan/builder.rs        | 32 +++++++++++++++++-----
 2 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/datafusion/core/tests/sqllogictests/test_files/join.slt 
b/datafusion/core/tests/sqllogictests/test_files/join.slt
index b940232a74..2f49c5b97c 100644
--- a/datafusion/core/tests/sqllogictests/test_files/join.slt
+++ b/datafusion/core/tests/sqllogictests/test_files/join.slt
@@ -532,17 +532,40 @@ FROM t1
 
 # test create table from query with LEFT join
 statement ok
-create table temp as 
+create table left_join_test as 
 with t1 as (select 1 as col1, 'asd' as col2), 
      t2 as (select 1 as col3, 'sdf' as col4)
 select col2, col4 from t1 left join t2 on col1 = col3
 
+# test create table from query with RIGHT join
+statement ok
+create table right_join_test as 
+with t1 as (select 1 as col1, 'asd' as col2), 
+     t2 as (select 1 as col3, 'sdf' as col4)
+select col2, col4 from t1 right join t2 on col1 = col3
+
+# test create table from query with FULL OUTER join
+statement ok
+create table full_join_test as 
+with t1 as (select 1 as col1, 'asd' as col2), 
+     t2 as (select 1 as col3, 'sdf' as col4)
+select col2, col4 from t1 full outer join t2 on col1 = col3
+
 statement ok
 drop table IF EXISTS t1;
 
 statement ok
 drop table IF EXISTS t2;
 
+statement ok
+drop table IF EXISTS left_join_test;
+
+statement ok
+drop table IF EXISTS right_join_test;
+
+statement ok
+drop table IF EXISTS full_join_test;
+
 # batch size
 statement ok
 set datafusion.execution.batch_size = 8192;
diff --git a/datafusion/expr/src/logical_plan/builder.rs 
b/datafusion/expr/src/logical_plan/builder.rs
index ec2a27542c..d72f6b462c 100644
--- a/datafusion/expr/src/logical_plan/builder.rs
+++ b/datafusion/expr/src/logical_plan/builder.rs
@@ -1041,11 +1041,18 @@ pub fn build_join_schema(
     right: &DFSchema,
     join_type: &JoinType,
 ) -> Result<DFSchema> {
+    fn nullify_fields(fields: &[DFField]) -> Vec<DFField> {
+        fields
+            .iter()
+            .map(|f| f.clone().with_nullable(true))
+            .collect()
+    }
+
     let right_fields = right.fields();
     let left_fields = left.fields();
 
     let fields: Vec<DFField> = match join_type {
-        JoinType::Inner | JoinType::Full | JoinType::Right => {
+        JoinType::Inner => {
             // left then right
             left_fields
                 .iter()
@@ -1055,14 +1062,25 @@ pub fn build_join_schema(
         }
         JoinType::Left => {
             // left then right, right set to nullable in case of not matched 
scenario
-            let right_fields_nullable: Vec<DFField> = right_fields
-                .iter()
-                .map(|f| f.clone().with_nullable(true))
-                .collect();
-
             left_fields
                 .iter()
-                .chain(&right_fields_nullable)
+                .chain(&nullify_fields(right_fields))
+                .cloned()
+                .collect()
+        }
+        JoinType::Right => {
+            // left then right, left set to nullable in case of not matched 
scenario
+            nullify_fields(left_fields)
+                .iter()
+                .chain(right_fields.iter())
+                .cloned()
+                .collect()
+        }
+        JoinType::Full => {
+            // left then right, all set to nullable in case of not matched 
scenario
+            nullify_fields(left_fields)
+                .iter()
+                .chain(&nullify_fields(right_fields))
                 .cloned()
                 .collect()
         }