diff --git a/doc/sql.extensions/README.substring_similar.txt b/doc/sql.extensions/README.substring_similar.txt
index 25424890cf..387aefd67c 100644
--- a/doc/sql.extensions/README.substring_similar.txt
+++ b/doc/sql.extensions/README.substring_similar.txt
@@ -14,7 +14,7 @@ Author:
 Syntax:
 
 <regular expression substring> ::=
-	SUBSTRING(<value> FROM <similar pattern> ESCAPE <escape character>)
+	SUBSTRING(<value> SIMILAR <similar pattern> ESCAPE <escape character>)
 
 <similar pattern> ::= <character value expression: substring similar expression>