SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 5)
   ExpressionList (children 1)
    Literal NULL (alias pid)
   ExpressionList (children 2)
    Identifier a.col1
    Function sum (alias summ) (children 1)
     ExpressionList (children 1)
      Identifier a.col2
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier table1 (alias a)
   Function or (children 1)
    ExpressionList (children 2)
     Function isNull (children 1)
      ExpressionList (children 1)
       Identifier pid
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier a.col2
       Identifier pid
   ExpressionList (children 1)
    Identifier a.col1
