SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function equals (children 1)
     ExpressionList (children 2)
      Function tuple (children 1)
       ExpressionList (children 3)
        Function toNullable (children 1)
         ExpressionList (children 1)
          Identifier number
        Function materialize (children 1)
         ExpressionList (children 1)
          Literal \'a\'
        Function materialize (children 1)
         ExpressionList (children 1)
          Function toUInt64OrNull (children 1)
           ExpressionList (children 1)
            Literal \'\'
      Function tuple (children 1)
       ExpressionList (children 3)
        Identifier number
        Function materialize (children 1)
         ExpressionList (children 1)
          Literal \'a\'
        Identifier number
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Function numbers (children 1)
       ExpressionList (children 1)
        Literal UInt64_1