diff --git a/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java b/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java
index 3504c3a2a9f..096bbac105f 100644
--- a/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java
+++ b/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java
@@ -305,7 +305,7 @@ public static String toBase64(String string) {
     return toBase64_(string.getBytes(UTF_8));
   }
 
-  /** SQL TO_BASE64(string)/BASE64(string) function for binary string. */
+  /** SQL TO_BASE64(string) function for binary string. */
   public static String toBase64(ByteString string) {
     return toBase64_(string.getBytes());
   }