Implement create view as functionality (#9794)

Implement create view as button in sqllab

Make CVAS configurable

Co-authored-by: bogdan kyryliuk <bogdankyryliuk@dropbox.com>

superset/models/sql_lab.py

@@ -19,7 +19,6 @@ import re
 from datetime import datetime
 from typing import Any, Dict
 
-# pylint: disable=ungrouped-imports
 import simplejson as json
 import sqlalchemy as sqla
 from flask import Markup
@@ -40,6 +39,7 @@ from sqlalchemy.orm import backref, relationship
 from superset import security_manager
 from superset.models.helpers import AuditMixinNullable, ExtraJSONMixin
 from superset.models.tags import QueryUpdater
+from superset.sql_parse import CtasMethod
 from superset.utils.core import QueryStatus, user_label
 
 
@@ -72,6 +72,7 @@ class Query(Model, ExtraJSONMixin):
     limit = Column(Integer)
     select_as_cta = Column(Boolean)
     select_as_cta_used = Column(Boolean, default=False)
+    ctas_method = Column(String(16), default=CtasMethod.TABLE)
 
     progress = Column(Integer, default=0)  # 1..100
     # # of rows in the result set or rows modified.