SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function count (children 1)
     ExpressionList
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.tables (alias t)
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier system.databases (alias db)
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier db.name
        Identifier t.database
   Function equals (children 1)
    ExpressionList (children 2)
     Identifier t.name
     Literal \'one\'