Directly support utf8view in nullif. #13379 (#13380)

Author: Omega359

datafusion/functions/src/core/nullif.rs

@@ -47,6 +47,7 @@ static SUPPORTED_NULLIF_TYPES: &[DataType] = &[
     DataType::Int64,
     DataType::Float32,
     DataType::Float64,
+    DataType::Utf8View,
     DataType::Utf8,
     DataType::LargeUtf8,
 ];

datafusion/sqllogictest/test_files/nullif.slt

@@ -101,3 +101,33 @@ query I
 SELECT NULLIF(NULL, NULL);
 ----
 NULL
+
+query T
+SELECT NULLIF(arrow_cast('a', 'Utf8View'), 'a');
+----
+NULL
+
+query T
+SELECT NULLIF('a', arrow_cast('a', 'Utf8View'));
+----
+NULL
+
+query T
+SELECT NULLIF(arrow_cast('a', 'Utf8View'), 'b');
+----
+a
+
+query T
+SELECT NULLIF('a', arrow_cast('b', 'Utf8View'));
+----
+a
+
+query T
+SELECT NULLIF(null, arrow_cast('a', 'Utf8View'));
+----
+NULL
+
+query T
+SELECT NULLIF(arrow_cast('a', 'Utf8View'), null);
+----
+a

datafusion/sqllogictest/test_files/string/string_view.slt

@@ -934,6 +934,26 @@ logical_plan
 01)Projection: to_timestamp(test.column1_utf8view, Utf8("a,b,c,d")) AS c
 02)--TableScan: test projection=[column1_utf8view]
 
+## Ensure no casts for nullif
+query TT
+EXPLAIN SELECT
+  nullif(column1_utf8view, 'a') as c
+FROM test;
+----
+logical_plan
+01)Projection: nullif(test.column1_utf8view, Utf8View("a")) AS c
+02)--TableScan: test projection=[column1_utf8view]
+
+## Ensure no casts for nullif
+query TT
+EXPLAIN SELECT
+  nullif(column1_utf8view, column1_utf8view) as c
+FROM test;
+----
+logical_plan
+01)Projection: nullif(test.column1_utf8view, test.column1_utf8view) AS c
+02)--TableScan: test projection=[column1_utf8view]
+
 ## Ensure no casts for binary operators
 # `~` operator (regex match)
 query TT