From 3900dc318797f0c829deb42ed9d723a30e3f60b0 Mon Sep 17 00:00:00 2001
From: Aviv Klasquin Komissar <avivklas@users.noreply.github.com>
Date: Tue, 19 Oct 2021 12:18:21 +0300
Subject: [PATCH] return non-nil result when calling exec with empty query
 (#973)

fixes #963
---
 sqlite3.go      |  4 ++++
 sqlite3_test.go | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/sqlite3.go b/sqlite3.go
index 5ac95709..d72bcb34 100644
--- a/sqlite3.go
+++ b/sqlite3.go
@@ -828,6 +828,10 @@ func (c *SQLiteConn) exec(ctx context.Context, query string, args []namedValue)
 		tail := s.(*SQLiteStmt).t
 		s.Close()
 		if tail == "" {
+			if res == nil {
+				// https://github.com/mattn/go-sqlite3/issues/963
+				res = &SQLiteResult{0, 0}
+			}
 			return res, nil
 		}
 		query = tail
diff --git a/sqlite3_test.go b/sqlite3_test.go
index 878ec495..5eddae98 100644
--- a/sqlite3_test.go
+++ b/sqlite3_test.go
@@ -1943,6 +1943,7 @@ var tests = []testing.InternalTest{
 	{Name: "TestManyQueryRow", F: testManyQueryRow},
 	{Name: "TestTxQuery", F: testTxQuery},
 	{Name: "TestPreparedStmt", F: testPreparedStmt},
+	{Name: "TestExecEmptyQuery", F: testExecEmptyQuery},
 }
 
 var benchmarks = []testing.InternalBenchmark{
@@ -2273,6 +2274,25 @@ func testPreparedStmt(t *testing.T) {
 	wg.Wait()
 }
 
+// testEmptyQuery is test for validating the API in case of empty query
+func testExecEmptyQuery(t *testing.T) {
+	db.tearDown()
+	res, err := db.Exec(" -- this is just a comment ")
+	if err != nil {
+		t.Fatalf("empty query err: %v", err)
+	}
+
+	_, err = res.LastInsertId()
+	if err != nil {
+		t.Fatalf("LastInsertId returned an error: %v", err)
+	}
+
+	_, err = res.RowsAffected()
+	if err != nil {
+		t.Fatalf("RowsAffected returned an error: %v", err)
+	}
+}
+
 // Benchmarks need to use panic() since b.Error errors are lost when
 // running via testing.Benchmark() I would like to run these via go
 // test -bench but calling Benchmark() from a benchmark test