SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 2)
    WithElement (children 1)
     Subquery (children 1)
      SelectWithUnionQuery (children 1)
       ExpressionList (children 1)
        SelectQuery (children 2)
         ExpressionList (children 2)
          Identifier col_a
          Identifier col_b
         TablesInSelectQuery (children 2)
          TablesInSelectQueryElement (children 1)
           TableExpression (children 1)
            Subquery (children 1)
             SelectWithUnionQuery (children 1)
              ExpressionList (children 1)
               SelectQuery (children 1)
                ExpressionList (children 2)
                 Literal \'a\' (alias col_a)
                 Literal Array_[\'b\', \'c\'] (alias col_b)
          TablesInSelectQueryElement (children 1)
           ArrayJoin (children 1)
            ExpressionList (children 1)
             Identifier col_b
    Subquery (alias group_a) (children 1)
     SelectWithUnionQuery (children 1)
      ExpressionList (children 1)
       SelectQuery (children 2)
        ExpressionList (children 1)
         Function groupArray (children 1)
          ExpressionList (children 1)
           Function tuple (children 1)
            ExpressionList (children 2)
             Identifier col_a
             Identifier col_b
        TablesInSelectQuery (children 1)
         TablesInSelectQueryElement (children 1)
          TableExpression (children 1)
           TableIdentifier table_x
   ExpressionList (children 2)
    Identifier group_a
    Function groupArray (children 1)
     ExpressionList (children 1)
      Function tuple (children 1)
       ExpressionList (children 2)
        Identifier col_a
        Identifier col_b
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier table_x
