SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function mapAdd (children 1)
     ExpressionList (children 2)
      Function tuple (children 1)
       ExpressionList (children 2)
        Function CAST (children 1)
         ExpressionList (children 2)
          Literal Array_[\'a\', \'b\']
          Literal \'Array(LowCardinality(String))\'
        Literal Array_[UInt64_1, UInt64_1]
      Function tuple (children 1)
       ExpressionList (children 2)
        Function array (children 1)
         ExpressionList (children 1)
          Identifier key
        Literal Array_[UInt64_1]
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Function values (children 1)
       ExpressionList (children 4)
        Literal \'key String\'
        Literal \'b\'
        Literal \'c\'
        Literal \'d\'
