SelectWithUnionQuery (children 2)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Function count (alias num) (children 1)
     ExpressionList (children 1)
      Function materialize (children 1)
       ExpressionList (children 1)
        Function toLowCardinality (children 1)
         ExpressionList (children 1)
          Literal UInt64_1
    Function hostName (alias hostName) (children 1)
     ExpressionList
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.query_log (alias a)
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier system.processes (alias b)
     TableJoin (children 1)
      Function and (children 1)
       ExpressionList (children 3)
        Function equals (children 1)
         ExpressionList (children 2)
          Identifier type
          Function toFixedString (children 1)
           ExpressionList (children 2)
            Function toNullable (children 1)
             ExpressionList (children 1)
              Literal \'QueryStart\'
            Literal UInt64_10
        Function greater (children 1)
         ExpressionList (children 2)
          Function dateDiff (children 1)
           ExpressionList (children 3)
            Literal \'second\'
            Identifier event_time
            Function now (children 1)
             ExpressionList
          Literal UInt64_5
        Function equals (children 1)
         ExpressionList (children 2)
          Identifier current_database
          Function currentDatabase (children 1)
           ExpressionList
 Identifier Null
