From 7e49ccf3dd3408bc9c4adb86f070d1e3d1f4c1e2 Mon Sep 17 00:00:00 2001
From: Jonah Gao <jonahgao@msn.com>
Date: Thu, 27 Jun 2024 01:41:54 +0800
Subject: [PATCH] Temporary Fix: Query error when grouping by case expressions
 (#11133)

---
 datafusion/core/src/physical_planner.rs       | 11 ++++++++---
 .../sqllogictest/test_files/group_by.slt      | 19 +++++++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/datafusion/core/src/physical_planner.rs b/datafusion/core/src/physical_planner.rs
index 52d976c45cf3..15f7555575e8 100644
--- a/datafusion/core/src/physical_planner.rs
+++ b/datafusion/core/src/physical_planner.rs
@@ -156,13 +156,18 @@ fn create_physical_name(e: &Expr, is_first_expr: bool) -> Result<String> {
         Expr::Case(case) => {
             let mut name = "CASE ".to_string();
             if let Some(e) = &case.expr {
-                let _ = write!(name, "{e} ");
+                let _ = write!(name, "{} ", create_physical_name(e, false)?);
             }
             for (w, t) in &case.when_then_expr {
-                let _ = write!(name, "WHEN {w} THEN {t} ");
+                let _ = write!(
+                    name,
+                    "WHEN {} THEN {} ",
+                    create_physical_name(w, false)?,
+                    create_physical_name(t, false)?
+                );
             }
             if let Some(e) = &case.else_expr {
-                let _ = write!(name, "ELSE {e} ");
+                let _ = write!(name, "ELSE {} ", create_physical_name(e, false)?);
             }
             name += "END";
             Ok(name)
diff --git a/datafusion/sqllogictest/test_files/group_by.slt b/datafusion/sqllogictest/test_files/group_by.slt
index f7f251e4b95c..04a1fcc78fe7 100644
--- a/datafusion/sqllogictest/test_files/group_by.slt
+++ b/datafusion/sqllogictest/test_files/group_by.slt
@@ -5135,3 +5135,22 @@ GROUP BY
     ts_chunk;
 ----
 2024-01-01T00:00:00 4
+
+# Issue: https://github.com/apache/datafusion/issues/11118
+statement ok
+CREATE TABLE test_case_expr(a INT, b TEXT) AS VALUES (1,'hello'), (2,'world')
+
+query T
+SELECT (CASE WHEN CONCAT(b, 'hello') = 'test' THEN 'good' ELSE 'bad' END) AS c 
+  FROM test_case_expr GROUP BY c;
+----
+bad
+
+query I rowsort
+SELECT (CASE a::BIGINT WHEN 1 THEN 1 END) AS c FROM test_case_expr GROUP BY c;
+----
+1
+NULL
+
+statement ok
+drop table test_case_expr