From 63dd5e61ac39d2b64558d98397b6a89b477c9a1c Mon Sep 17 00:00:00 2001
From: Alex Chi Z <iskyzh@gmail.com>
Date: Mon, 15 Jan 2024 17:03:57 +0800
Subject: [PATCH] docs: update df-repr expr

---
 docs/src/datafusion.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/docs/src/datafusion.md b/docs/src/datafusion.md
index 8d0529c3..94049717 100644
--- a/docs/src/datafusion.md
+++ b/docs/src/datafusion.md
@@ -72,6 +72,8 @@ LogicalJoin { #0 = #3 }
 
 in the optd representation.
 
+For SQL expressions, the optd Datafusion representation does not do cost-based searches on expressions, though this is supported in optd-core. Each SQL expression can only have one binding in the current implementation.
+
 ## Explain
 
 We use risinglightdb's pretty-xmlish crate and implement a custom explain format for Datafusion plan nodes.