CreateQuery mv_source (children 3)
 Identifier mv_source
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration a (children 1)
    DataType Int64
   ColumnDeclaration insert_time (children 1)
    DataType DateTime
 Storage definition (children 2)
  Function MergeTree (children 1)
   ExpressionList
  Identifier insert_time