I have a function with a conditional result. Based on the argument value it should either return varchar or int or uuid or timestamp.
What should the return type of that function be?
CodePudding user response：
SQL is strictly typed. The simple solution is to return one text field. Every value can be cast to text. (You might add a second return column holding the type name as meta information.)
Alternatively, return four typed fields (varchar, int, uuid, timestamp), and only fill one of them, depending on the result.
A polymorphic function would only be an option if you can tell the return type at call time and pass typed input accordingly.
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