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 system.columns
   Function equals (children 1)
    ExpressionList (children 2)
     Identifier database
     Literal \'_temporary_and_external_tables\'
