pgstmt: add short hand on conflict do nothing

pgstmt/insert.go

@@ -20,6 +20,10 @@ type InsertStatement interface {
 
 	OnConflict(f func(b ConflictTarget)) ConflictAction
 
+	// OnConflictDoNothing is the shortcut for
+	// OnConflict(func(b ConflictTarget) {}).DoNothing()
+	OnConflictDoNothing()
+
 	// OnConflictIndex is the shortcut for
 	// OnConflict(func(b ConflictTarget) {
 	//		b.Index(target...)
@@ -104,6 +108,14 @@ func (st *insertStmt) OnConflict(f func(b ConflictTarget)) ConflictAction {
 	return &st.conflict.action
 }
 
+func (st *insertStmt) OnConflictDoNothing() {
+	st.conflict = &conflict{
+		action: conflictAction{
+			doNothing: true,
+		},
+	}
+}
+
 func (st *insertStmt) OnConflictIndex(target ...string) ConflictAction {
 	return st.OnConflict(func(b ConflictTarget) {
 		b.Index(target...)

pgstmt/insert_test.go

@@ -34,6 +34,27 @@ func TestInsert(t *testing.T) {
 		)
 	})
 
+	t.Run("insert on conflict do nothing", func(t *testing.T) {
+		q, args := pgstmt.Insert(func(b pgstmt.InsertStatement) {
+			b.Into("users")
+			b.Columns("username", "name")
+			b.Value("tester1", "Tester 1")
+			b.OnConflictDoNothing()
+			b.Returning("id")
+		}).SQL()
+
+		assert.Equal(t,
+			"insert into users (username, name) values ($1, $2) on conflict do nothing returning id",
+			q,
+		)
+		assert.EqualValues(t,
+			[]any{
+				"tester1", "Tester 1",
+			},
+			args,
+		)
+	})
+
 	t.Run("insert select", func(t *testing.T) {
 		q, args := pgstmt.Insert(func(b pgstmt.InsertStatement) {
 			b.Into("films")