From 20bcdb320ab13d507eac6dff1f17f71123279d27 Mon Sep 17 00:00:00 2001
From: Matt Beanland <beanland@live.com.au>
Date: Fri, 21 Aug 2026 22:17:09 +0930
Subject: [PATCH] fix: string_position is zero based, and nil when the
 substring is absent

---
 lib/expr.ex | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/expr.ex b/lib/expr.ex
index 4f86c90..d4ea67e 100644
--- a/lib/expr.ex
+++ b/lib/expr.ex
@@ -1462,11 +1462,11 @@ defmodule AshSql.Expr do
       %Fragment{
         embedded?: pred_embedded?,
         arguments: [
-          raw: "#{bindings.sql_behaviour.strpos_function()}((",
+          raw: "(NULLIF(#{bindings.sql_behaviour.strpos_function()}((",
           expr: left,
           raw: "), (",
           expr: right,
-          raw: "))"
+          raw: ")), 0) - 1)"
         ]
       },
       bindings,