SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 1)
    Identifier f2
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Function merge (children 1)
       ExpressionList (children 2)
        Function currentDatabase (children 1)
         ExpressionList
        Literal \'^abc$\'
   Function equals (children 1)
    ExpressionList (children 2)
     Identifier f1
     Literal \'a\'
   Function equals (children 1)
    ExpressionList (children 2)
     Identifier _table
     Literal \'abc\'
