[firebird-support] Why this sql not work ?

[nathanelrick]

hello,

Select
  Field1,
  (select ...) AS MyFIELD2
  IIF(MyField is null, select ...., Null) As MYField3
From
  ....

it's not work, it's say unknow "MyField"
but if i replace MyFIELD2 by Field1 it's work ...

is their any workaround to make this SQL work ?