SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function count (children 1)
     ExpressionList
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier tab
   Function equals (children 1)
    ExpressionList (children 2)
     Function arrayElement (children 1)
      ExpressionList (children 2)
       Identifier map_fixed
       Literal \'K2\'
     Function toFixedString (children 1)
      ExpressionList (children 2)
       Literal \'V2\'
       Literal UInt64_2
