From dd6be6b9b641a736cd4c9a4528ad9c6ddb089fdf Mon Sep 17 00:00:00 2001
From: Sebastiaan de Schaetzen <sebastiaan.de.schaetzen@gmail.com>
Date: Thu, 8 May 2025 11:14:41 +0200
Subject: [PATCH] Return a verifiable error if no results were returned

---
 errors.go     |  5 +++++
 query.go      |  2 +-
 query_test.go | 11 ++++++++++-
 3 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 errors.go

diff --git a/errors.go b/errors.go
new file mode 100644
index 0000000..d691fe5
--- /dev/null
+++ b/errors.go
@@ -0,0 +1,5 @@
+package mysqlite
+
+import "errors"
+
+var ErrNoRows = errors.New("mysqlite: no rows returned")
diff --git a/query.go b/query.go
index 73ef203..362d0c9 100644
--- a/query.go
+++ b/query.go
@@ -116,7 +116,7 @@ func (q *Query) ScanSingle(results ...any) (rerr error) {
 		return err
 	}
 	if !hasResult {
-		return fmt.Errorf("did not return any rows")
+		return ErrNoRows
 	}
 
 	// Scan its columns
diff --git a/query_test.go b/query_test.go
index 81bf575..14144f9 100644
--- a/query_test.go
+++ b/query_test.go
@@ -1,6 +1,7 @@
 package mysqlite
 
 import (
+	"errors"
 	"github.com/stretchr/testify/require"
 	"testing"
 )
@@ -19,6 +20,14 @@ func TestSimpleQuery(t *testing.T) {
 	require.Equal(t, 1, count, "expected empty count")
 }
 
+func TestSimpleQueryWithNoResults(t *testing.T) {
+	db := openTestDb(t)
+	var count int
+	err := db.Query("select 1 from mytable where key=999").ScanSingle(&count)
+	require.Equal(t, ErrNoRows, err)
+	require.True(t, errors.Is(err, ErrNoRows))
+}
+
 func TestSimpleQueryWithArgs(t *testing.T) {
 	db := openTestDb(t)
 	var value string
@@ -102,7 +111,7 @@ func TestQueryWithPointerStringArguments(t *testing.T) {
 
 func TestQueryWithPointerStringArgumentsCanSetToNull(t *testing.T) {
 	db := openTestDb(t)
-	db.Query("update mytable set value=NULL where key = 'foo'").MustExec()
+	db.Query("update mytable set value=null where key = 'foo'").MustExec()
 	myString := "some string"
 	var result *string
 	result = &myString