modify the return type

Author: Weijun-H

datafusion/expr/src/built_in_function.rs

@@ -617,7 +617,18 @@ impl BuiltinScalarFunction {
             BuiltinScalarFunction::ArrayReplaceAll => Ok(input_expr_types[0].clone()),
             BuiltinScalarFunction::ArraySlice => Ok(input_expr_types[0].clone()),
             BuiltinScalarFunction::ArrayToString => Ok(Utf8),
-            BuiltinScalarFunction::ArrayUnion | BuiltinScalarFunction::ArrayIntersect => {
+            BuiltinScalarFunction::ArrayIntersect => {
+                match (input_expr_types[0].clone(), input_expr_types[1].clone()) {
+                    (DataType::Null, DataType::Null) | (DataType::Null, _) => {
+                        Ok(DataType::Null)
+                    }
+                    (_, DataType::Null) => {
+                        Ok(List(Arc::new(Field::new("item", Null, true))))
+                    }
+                    (dt, _) => Ok(dt),
+                }
+            }
+            BuiltinScalarFunction::ArrayUnion => {
                 match (input_expr_types[0].clone(), input_expr_types[1].clone()) {
                     (DataType::Null, dt) => Ok(dt),
                     (dt, DataType::Null) => Ok(dt),

datafusion/physical-expr/src/array_expressions.rs

@@ -1631,24 +1631,36 @@ fn general_set_op(
     set_op: SetOp,
 ) -> Result<ArrayRef> {
     match (array1.data_type(), array2.data_type()) {
-        // Null type
-        (DataType::Null, DataType::List(field))
-        | (DataType::List(field), DataType::Null) => {
-            let array = match array1.data_type() {
-                DataType::Null => as_list_array(&array2)?,
-                _ => as_list_array(&array1)?,
-            };
+        (DataType::Null, DataType::List(field)) => {
+            if set_op == SetOp::Intersect {
+                return make_array(dbg!(&[]));
+            }
+            let array = as_list_array(&array2)?;
             general_array_distinct::<i32>(array, field)
         }
-        (DataType::Null, DataType::LargeList(field))
-        | (DataType::LargeList(field), DataType::Null) => {
-            let array = match array1.data_type() {
-                DataType::Null => as_large_list_array(&array2)?,
-                _ => as_large_list_array(&array1)?,
-            };
+
+        (DataType::List(field), DataType::Null) => {
+            if set_op == SetOp::Intersect {
+                return make_array(dbg!(&[]));
+            }
+            let array = as_list_array(&array1)?;
+            general_array_distinct::<i32>(array, field)
+        }
+        (DataType::Null, DataType::LargeList(field)) => {
+            if set_op == SetOp::Intersect {
+                return make_array(&[]);
+            }
+            let array = as_large_list_array(&array2)?;
+            general_array_distinct::<i64>(array, field)
+        }
+        (DataType::LargeList(field), DataType::Null) => {
+            if set_op == SetOp::Intersect {
+                return make_array(&[]);
+            }
+            let array = as_large_list_array(&array1)?;
             general_array_distinct::<i64>(array, field)
         }
-        (DataType::Null, DataType::Null) => Ok(array1.clone()),
+        (DataType::Null, DataType::Null) => make_array(&[]),
 
         (DataType::List(_), DataType::List(_)) => {
             let array1 = as_list_array(&array1)?;

datafusion/sqllogictest/test_files/array.slt

@@ -2116,7 +2116,7 @@ select array_union(null, []);
 query ?
 select array_union(null, null);
 ----
-NULL
+[]
 
 # array_union scalar function #11
 query ?
@@ -3046,12 +3046,12 @@ select array_intersect([], []);
 query ?
 select array_intersect([1, 1, 2, 2, 3, 3], null);
 ----
-[1, 2, 3]
+[]
 
 query ?
 select array_intersect(null, [1, 1, 2, 2, 3, 3]);
 ----
-[1, 2, 3]
+[]
 
 query ?
 select array_intersect([], null);
@@ -3066,7 +3066,7 @@ select array_intersect(null, []);
 query ?
 select array_intersect(null, null);
 ----
-NULL
+[]
 
 query ??????
 SELECT  list_intersect(make_array(1,2,3), make_array(2,3,4)),