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