Change date difference with CASE calculation - sql

Question

I have a holding table for data, before adding to a final table in my database.
Within that table is a datediff calculation, which returns the number of days in a month.
However, this is baased on projects and what I need to do is look up the Project ID in another table, to see whether the TimeID (Year/Month) is equal to either the Start- or End-Date of the project.
When it matches either, it needs to change the number of days for that month to either Month-Start to Project-Finish (if it's the end month) or Project-Start to Month-End (if it's the start month).
I've tried to do this with the following script but I get the errors:
*** This bit is sorted, please see below ***
Msg 156, Level 15, State 1, Line 15
Incorrect syntax near the keyword 'FROM'.
Msg 102, Level 15, State 1, Line 23
Incorrect syntax near 'A'.
*** This bit is sorted, please see below ***
* EDIT *
Thanks to Anton, I've added the required END to my CASE statement, but I now get a different set of errors (probably down to my syntax):
Msg 207, Level 16, State 1, Line 23
Invalid column name 'TimeID'.
Msg 207, Level 16, State 1, Line 20
Invalid column name 'TimeID'.
Msg 207, Level 16, State 1, Line 26
Invalid column name 'ID'.
Msg 207, Level 16, State 1, Line 28
Invalid column name 'ID'.
Please help if you can.
The script is:
UPDATE FAC
SET FAC.[SignedData] =
CASE
WHEN FAC.[TIMEID] = A.[Start_TimeID] THEN
CASE
WHEN pd.[Start_Date] >= GETDATE() THEN datediff(day,pd.[Start_Date],pt.[Period_End])
WHEN pd.[Start_Date] < GETDATE() THEN datediff(day,GETDATE(),pt.[Period_End])
END
WHEN FAC.[TIMEID] = A.[End_TimeID] THEN
CASE
WHEN pd.[End_Date] >= GETDATE() THEN datediff(day,getdate(),pd.[End_Date])
WHEN pd.[End_Date] < GETDATE() THEN '0'
END
END
FROM Temp_Fac2Programme FAC
JOIN
(
SELECT
pd.[TimeID], pd.[Start_TimeID], pd.[End_TimeID], pt.[Period_Start], pt.[Period_End]
FROM ProjectDates pd
JOIN ProjectTimeID pt
on pd.[TimeID] = pt.[TimeID]
) A
ON A.[ID] = FAC.[Project]
Where A.[ID] = FAC.[Project]
GO
NB - SIGNEDDATA is the number of days in the month.
* Example Data *
Temp_Fac2Programme (FAC) contains:
ACCOUNT CATEGORY DATASRC PROFITCENTRE PROJECT RPTCURRENCY TIMEID SIGNEDDATA SOURCE
REMAIN_DAYS_FLAG ACTUAL DS_FLAGS B9059 AAA_7915_BBOY LC 20130100 34.0000000000 0
ProjectDates (pd) contains:
PROJECT_ID START_TIMEID END_TIMEID START_DATE END_DATE TOTAL_DAYS
PAG_5244_CASH 20110400 20120300 2011-04-01 2012-03-31 365
ProjectTimeID (pt) contains:
TIMEID PERIOD_START PERIOD_END DAYS_IN_PERIOD PCMONTHSTAT
20140600 2014-05-31 2014-06-27 27 F

Answer 1

As of the current (edited) version, it's basically what error messages say:
You use pd.[TimeID] in two places, but there is no TimeID column in ProjectDates (for now, I have no idea what you meant here).
Your subquery (aliased to A) has no ID column. The likely fix is adding pd.[Project_ID] as ID into the subquery's list of selected fields.