SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Identifier x
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 3)
          ExpressionList (children 1)
           Function toFixedString (alias x) (children 1)
            ExpressionList (children 2)
             Function if (children 1)
              ExpressionList (children 3)
               Function less (children 1)
                ExpressionList (children 2)
                 Identifier number
                 Literal UInt64_20
               Literal \'\'
               Literal \'Hello\'
             Literal UInt64_5
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier system.numbers
          Literal UInt64_50
   Function notEquals (children 1)
    ExpressionList (children 2)
     Identifier x
     Literal \'\\0\\0\\0\\0\\0\'
