feat: added raw query calls (uptrace#596)

* feat: added raw query calls

internal/dbtest/db_test.go

@@ -254,6 +254,7 @@ func TestDB(t *testing.T) {
 		{testJSONInterface},
 		{testJSONValuer},
 		{testSelectBool},
+		{testRawQuery},
 		{testFKViolation},
 		{testWithForeignKeysAndRules},
 		{testWithForeignKeys},
@@ -820,6 +821,14 @@ func testSelectBool(t *testing.T, db *bun.DB) {
 	require.False(t, flag)
 }
 
+func testRawQuery(t *testing.T, db *bun.DB) {
+	var num int
+	err := db.Raw("SELECT ?", 123).Scan(ctx, &num)
+
+	require.NoError(t, err)
+	require.Equal(t, 123, num)
+}
+
 func testFKViolation(t *testing.T, db *bun.DB) {
 	type Deck struct {
 		ID     int `bun:",pk,autoincrement"`

query_raw.go

@@ -0,0 +1,47 @@
+package bun
+
+import (
+	"context"
+	"github.com/uptrace/bun/schema"
+)
+
+type RawQuery struct {
+	baseQuery
+
+	query string
+	args  []interface{}
+}
+
+func (db *DB) Raw(query string, args ...interface{}) *RawQuery {
+	return &RawQuery{
+		baseQuery: baseQuery{
+			db:   db,
+			conn: db.DB,
+		},
+		query: query,
+		args:  args,
+	}
+}
+
+func (q *RawQuery) Scan(ctx context.Context, dest ...interface{}) error {
+	if q.err != nil {
+		return q.err
+	}
+
+	model, err := q.getModel(dest)
+	if err != nil {
+		return err
+	}
+
+	query := q.db.format(q.query, q.args)
+	_, err = q.scan(ctx, q, query, model, true)
+	return err
+}
+
+func (q *RawQuery) AppendQuery(fmter schema.Formatter, b []byte) ([]byte, error) {
+	return fmter.AppendQuery(b, q.query, q.args), nil
+}
+
+func (q *RawQuery) Operation() string {
+	return "SELECT"
+}