SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 4)
    Function toStartOfMinute (alias dt_m) (children 1)
     ExpressionList (children 1)
      Identifier datetime
    Function count (children 1)
     ExpressionList
    Function divide (children 1)
     ExpressionList (children 2)
      Function sum (children 1)
       ExpressionList (children 1)
        Identifier block_count
      Function sum (children 1)
       ExpressionList (children 1)
        Identifier duration
    Function avg (children 1)
     ExpressionList (children 1)
      Function divide (children 1)
       ExpressionList (children 2)
        Identifier block_count
        Identifier duration
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier projection_test
   ExpressionList (children 1)
    Identifier dt_m
   ExpressionList (children 1)
    OrderByElement (children 1)
     Identifier dt_m