Change The Value Of Computed Column In Specific Conditions

I have a table for Library Circulation that have a column named 'Delay'. This column is a computed column, but it should be changed until the 'IsReturned' (another column in this t

Solution 1:

Referring to a computed column in a computed column definition is not allowed. You need to record the times that the item is checked out and returned rather than using a BIT field. You can use those values to define your computed column. For example:

CREATE TABLE Checkouts
(
    CheckoutId INT IDENTITY NOT NULL PRIMARY KEY, 
    CheckedOut DATETIME NOT NULL DEFAULT (getdate()), 
    CheckedIn DATETIME NULL, 
    DelayDays AS (datediff(day, CheckedOut, COALESCE(CheckedIn, getdate()))) 
)