From 6fad732f05bc7abfcb22cec8b6d3b16599bede90 Mon Sep 17 00:00:00 2001
From: Michael Xu <xzhseh@gmail.com>
Date: Sat, 3 Feb 2024 17:34:11 -0500
Subject: [PATCH] add comment to best illustrate the purpose

---
 src/frontend/src/binder/expr/mod.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/frontend/src/binder/expr/mod.rs b/src/frontend/src/binder/expr/mod.rs
index b23350509176f..dc8f4c453bf01 100644
--- a/src/frontend/src/binder/expr/mod.rs
+++ b/src/frontend/src/binder/expr/mod.rs
@@ -469,6 +469,8 @@ impl Binder {
         Ok(func_call.into())
     }
 
+    /// The optimization check for the following case-when expression pattern
+    /// e.g., select case 1 when (...) then (...) else (...) end;
     fn check_constant_case_when_optimization(
         &mut self,
         conditions: Vec<Expr>,