Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 4)
    ExpressionList (children 2)
     Identifier k
     Function groupArrayMovingSum (children 1)
      ExpressionList (children 1)
       Identifier v
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Subquery (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 3)
           ExpressionList (children 1)
            Asterisk
           TablesInSelectQuery (children 1)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              TableIdentifier moving_sum_num
           ExpressionList (children 2)
            OrderByElement (children 1)
             Identifier k
            OrderByElement (children 1)
             Identifier dt
    ExpressionList (children 1)
     Identifier k
    ExpressionList (children 1)
     OrderByElement (children 1)
      Identifier k
