SQL Server CASE using 2 different Tables - sql

Question

I am trying to use two different tables in a CASE statement but am really struggling. Most of my SQL knowledge is self taught so finding it a bit of a struggle!
The result I am trying to achieve is if TC.ClockingStatus WHEN 1 then '24' (1st Table) if not WHEN OP.Status WHEN 'C' THEN 99 WHEN 'I' THEN 50 ELSE 0 END (2nd Table) AS Status.
This is my current statement:
SELECT TOP (100) PERCENT
RTRIM(OP.Standard_Op) AS TaskDescription,
OP.Op_Number AS OpStep,
CAST(CAST(OP.Works_Order_Number AS DECIMAL(12, 2)) AS NVARCHAR(50)) AS OrderCode,
CASE OP.Status
WHEN 'C' THEN 99
WHEN 'I' THEN 50
ELSE 0
END AS Status,
CAST(OP.Op_Number AS varchar(50)) AS OpCode,
CAST(CAST(OP.Works_Order_Number AS decimal(12, 2)) AS nvarchar(50)) + '_' + CAST(OP.Op_Number AS nvarchar(50)) AS JobCode,
TC.ClockingStatus
FROM
dbo.PROGRESS AS OP
INNER JOIN
dbo.vOrcData_ActiveOperations AS AW ON AW.Works_Order = OP.Works_Order_Number
AND AW.Op_Number = OP.Op_Number
INNER JOIN
dbo.WOHEAD AS WH ON WH.Works_Order = OP.Works_Order_Number
INNER JOIN
dbo.RESOURCE AS RR ON RR.Resource_Code = OP.Original_Resource_Code
LEFT OUTER JOIN
dbo.Techman_WOCLOCK AS TC ON OP.Works_Order_Number = TC.OrderCode
AND OP.Op_Number = TC.OpStep
LEFT OUTER JOIN
dbo.MEMO_FIELDS_SQL ON dbo.MEMO_FIELDS_SQL.Memo_Unique = OP.Man_Memo_Unique
LEFT OUTER JOIN
(SELECT
Allocated_WO_Num, Sub_Con_Op_No,
MAX(Date_Promised) AS Date_Promised
FROM
dbo.PODETAIL AS PODETAIL_1
GROUP BY
Allocated_WO_Num, Sub_Con_Op_No) AS PODETAIL ON PODETAIL.Allocated_WO_Num = OP.Works_Order_Number
AND PODETAIL.Sub_Con_Op_No = OP.Op_Number
LEFT OUTER JOIN
(SELECT
Works_Order, Operation,
SUM(Operation_Time) AS TimeComplete
FROM
dbo.WOCLOCK
GROUP BY
Works_Order, Operation) AS CLOCKEDTIME ON WH.Works_Order = CLOCKEDTIME.Works_Order AND OP.Op_Number = CLOCKEDTIME.Operation

Answer 1

It's possible to use different columns/expressions in a case statement,
but you can't name the column before the first WHEN, like you do.
Try this:
CASE
WHEN TC.ClockingStatus = 1 THEN 24
WHEN OP.Status = 'C' THEN 99
WHEN OP.Status = 'I' THEN 50
ELSE 0 END
The expressions inside a WHEN test can be as complicated as you like. You can even nest CASE statements:
CASE
WHEN TC.ClockingStatus = 1 THEN 24
ELSE CASE OP.Status
WHEN 'C' THEN 99
WHEN 'I' THEN 50
ELSE 0
END
END

Answer 2

I think your problem is that you are trying to use the CASE form:
CASE <Field> WHEN <Value> THEN <Result>
What you need to use is the form:
CASE WHEN <Any condition no matter how complicated> THEN <Result>
Example:
CASE OP.Status WHEN 'C' THEN 99 ELSE 0 END
Can also be used as:
CASE WHEN OP.Status='C' THEN 99 ELSE 0 END