SSRS =Switch not altering text - tsql

Question

Can anyone please help explain why when the first switch value is 0 it will change to red, but when it is the text value "Expired" (altered with a CASE WHEN in the query) the text remains black.
This does not work:
=Switch(Fields!Days_Until_Expiry.Value = "Expired", "Red"
, Fields!Days_Until_Expiry.Value > 1 AND Fields!Days_Until_Expiry.Value < 90, "Orange"
, Fields!Days_Until_Expiry.Value > 90, "Green")
, CASE
WHEN DATEDIFF(d, c.Date_Expiration, SYSDATETIME()) > 0
THEN 'Expired'
[...]
This does work:
=Switch(Fields!Days_Until_Expiry.Value = 0, "Red"
, Fields!Days_Until_Expiry.Value > 1 AND Fields!Days_Until_Expiry.Value < 90, "Orange"
, Fields!Days_Until_Expiry.Value > 90, "Green")
, CASE
WHEN DATEDIFF(d, c.Date_Expiration, SYSDATETIME()) > 0
THEN 0
[...]
This is going to be a simple explanation I haven't been able to find, isn't it...
[EDIT]:
Seems the problem is in the query.
, CASE
WHEN DATEDIFF(d, c.Date_Expiration, SYSDATETIME()) > 0
THEN 'Expired'
ELSE ABS(DATEDIFF(d, c.Date_Expiration, SYSDATETIME()))
END AS Days_Until_Expiry
How can I make this query work and have SSRS pick up both the returned int values and the text string?

Answer 1

From what I see the switch statement is unable to determine whether Days_Until_Expiry is returning a string or an int. Ideally (depending on your version of SSRS) you should have seen a #Error instead of just a blank textbox.
I tried to recreate this (in SSRS 2008R2) but I ended up seeing the #Error in the textbox with an error message in my output window:
The Value expression for the textrun ‘Textbox3.Paragraphs[0].TextRuns[0]’ contains an error: Input string was not in a correct format.
When you updated your CASE statement so that Days_Until_Expiry always returns an int the Switch was able to evaluate all conditions correctly.
[Edit]: If you are trying to get string and int values into SSRS so that you can further evaluate the status to be "Red", "Orange" or "Green", you can combine the CASE and SWITCH logic into to the CASE statement as follows:
CASE
WHEN DATEDIFF(d, c.Date_Expiration, SYSDATETIME()) > 0
THEN 'Red'
WHEN ABS(DATEDIFF(d, c.Date_Expiration, SYSDATETIME())) > 1 AND ABS(DATEDIFF(d, c.Date_Expiration, SYSDATETIME())) < 90
THEN 'Orange'
ELSE 'Green'
END AS Days_Until_Expiry
You can then directly display Days_Until_Expiry without using any SWITCH statement. Let me know if I am missing something.