make query work

Author: dharanad

datafusion/expr/src/type_coercion/binary.rs

@@ -890,7 +890,7 @@ fn dictionary_coercion(
 /// 2. Data type of the other side should be able to cast to string type
 fn string_concat_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {
     use arrow::datatypes::DataType::*;
-    string_coercion(lhs_type, rhs_type).or(match (lhs_type, rhs_type) {
+    string_coercion_duplicate(lhs_type, rhs_type).or(match (lhs_type, rhs_type) {
         (Utf8, from_type) | (from_type, Utf8) => {
             string_concat_internal_coercion(from_type, &Utf8)
         }
@@ -939,6 +939,20 @@ fn string_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType>
     }
 }
 
+fn string_coercion_duplicate(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {
+    use arrow::datatypes::DataType::*;
+    match (lhs_type, rhs_type) {
+        // If Utf8View is in any side, we coerce to Utf8.
+        (Utf8View, Utf8View | Utf8 | LargeUtf8) | (Utf8 | LargeUtf8, Utf8View) => {
+            Some(Utf8)
+        }
+        // Then, if LargeUtf8 is in any side, we coerce to LargeUtf8.
+        (LargeUtf8, Utf8 | LargeUtf8) | (Utf8, LargeUtf8) => Some(LargeUtf8),
+        (Utf8, Utf8) => Some(Utf8),
+        _ => None,
+    }
+}
+
 fn numeric_string_coercion(lhs_type: &DataType, rhs_type: &DataType) -> Option<DataType> {
     use arrow::datatypes::DataType::*;
     match (lhs_type, rhs_type) {

datafusion/sqllogictest/test_files/string_view.slt

@@ -379,3 +379,12 @@ select t.dt from dates t where arrow_cast('2024-01-01', 'Utf8View') < t.dt;
 
 statement ok
 drop table dates;
+
+statement ok
+create table temp as values ('value1', arrow_cast('one', 'Utf8View')), ('value1', arrow_cast('two', 'Utf8View'));
+
+query T
+select column2||'ff' from temp;
+----
+oneff
+twoff