Add support Upsert to model query

builder_mysql.go

@@ -90,6 +90,9 @@ func (b *MysqlBuilder) Upsert(table string, cols Params, constraints ...string)
 	}
 
 	q.sql += " ON DUPLICATE KEY UPDATE " + strings.Join(lines, ", ")
+	q.rawSQL, q.placeholders = b.db.processSQL(q.sql)
+
+	q.Bind(q.params)
 
 	return q
 }

model_query.go

@@ -172,3 +172,27 @@ func (q *ModelQuery) Delete() error {
 	_, err := q.builder.Delete(q.model.tableName, HashExp(pk)).WithContext(q.ctx).Execute()
 	return err
 }
+
+// Upsert creates a Query that represents an UPSERT SQL statement.
+// Upsert inserts a row into the table if the primary key or unique index is not found.
+// Otherwise it will update the row with the new values.
+// The keys of cols are the column names, while the values of cols are the corresponding column
+// values to be inserted.
+func (q *ModelQuery) Upsert(attrs ...string) error {
+	if q.lastError != nil {
+		return q.lastError
+	}
+	pk := q.model.pk()
+	if len(pk) == 0 {
+		return MissingPKError
+	}
+	var pks []string
+
+	cols := q.model.columns(attrs, q.exclude)
+	for name := range pk {
+		cols[name] = pk[name]
+		pks = append(pks, name)
+	}
+	_, err := q.builder.Upsert(q.model.tableName, Params(cols), pks...).WithContext(q.ctx).Execute()
+	return err
+}

model_query_test.go

@@ -236,3 +236,105 @@ func TestModelQuery_Delete(t *testing.T) {
 	var a int
 	assert.NotNil(t, db.Model(&a).Delete())
 }
+
+func TestModelQuery_Upsert(t *testing.T) {
+	db := getPreparedDB()
+	defer db.Close()
+
+	id := 2
+	name := "test"
+	email := "test@example.com"
+	{
+		// updating normally
+		customer := Customer{
+			ID:    id,
+			Name:  name,
+			Email: email,
+		}
+		err := db.Model(&customer).Upsert()
+		if assert.Nil(t, err) {
+			var c Customer
+			db.Select().From("customer").Where(HashExp{"ID": id}).One(&c)
+			assert.Equal(t, name, c.Name)
+			assert.Equal(t, email, c.Email)
+			assert.Equal(t, 0, c.Status)
+		}
+	}
+
+	{
+		// updating without primary keys
+		item2 := Item{
+			Name: name,
+		}
+		err := db.Model(&item2).Upsert()
+		assert.Equal(t, MissingPKError, err)
+	}
+
+	{
+		// updating all fields
+		customer := CustomerPtr{
+			ID:    &id,
+			Name:  name,
+			Email: &email,
+		}
+		err := db.Model(&customer).Upsert()
+		if assert.Nil(t, err) {
+			assert.Equal(t, id, *customer.ID)
+			var c CustomerPtr
+			db.Select().From("customer").Where(HashExp{"ID": id}).One(&c)
+			assert.Equal(t, name, c.Name)
+			if assert.NotNil(t, c.Email) {
+				assert.Equal(t, email, *c.Email)
+			}
+			assert.Nil(t, c.Status)
+		}
+	}
+
+	{
+		// updating selected fields only
+		id = 3
+		customer := CustomerPtr{
+			ID:    &id,
+			Name:  name,
+			Email: &email,
+		}
+		err := db.Model(&customer).Upsert("Name", "Email")
+		if assert.Nil(t, err) {
+			assert.Equal(t, id, *customer.ID)
+			var c CustomerPtr
+			db.Select().From("customer").Where(HashExp{"ID": id}).One(&c)
+			assert.Equal(t, name, c.Name)
+			if assert.NotNil(t, c.Email) {
+				assert.Equal(t, email, *c.Email)
+			}
+			if assert.NotNil(t, c.Status) {
+				assert.Equal(t, 2, *c.Status)
+			}
+		}
+	}
+
+	{
+		// inserting normally
+		customer := Customer{
+			ID:    5,
+			Name:  name,
+			Email: email,
+		}
+		err := db.Model(&customer).Upsert()
+		if assert.Nil(t, err) {
+			assert.Equal(t, 5, customer.ID)
+			var c Customer
+			db.Select().From("customer").Where(HashExp{"ID": 5}).One(&c)
+			assert.Equal(t, name, c.Name)
+			assert.Equal(t, email, c.Email)
+			assert.Equal(t, 0, c.Status)
+			assert.False(t, c.Address.Valid)
+		}
+	}
+
+	{
+		// updating non-struct
+		var a int
+		assert.NotNil(t, db.Model(&a).Upsert())
+	}
+}