Referencing created colum

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Hi all, I have this code, I want to make reference to some of the created columns to calculate another column.

I want to use the "Cycle" and the "Idle" to display in a separate column where W.[Index] = 'A'.

I have tried using:

CASE WHEN a.[Index] = 'A' THEN Cycle ELSE NULL END AS [CycleTime (s)],
CASE WHEN a.[Index] = 'A' THEN Idle ELSE NULL END AS [IdleTime (s)],

But keeps throwing error, I guess i need to create a temp table which is where am challenged. please assist

What I have tried:

temp As 

(SELECT identityFaceDMC, 
DATEDIFF(SECOND, MIN(UNITMeanTimeDiam), MAX(UNITMeanTimeDiam)) AS delay_UNIT,
DATEDIFF(SECOND, MIN(WrappingTimeDiam), MAX(WrappingTimeDiam)) AS delay_wrap,
DATEDIFF(SECOND, MIN(PushTimeDiam), MAX(PushTimeDiam)) AS delay_Push				  
FROM orig AS orig_1 GROUP BY identityFaceDMC)	

SELECT TOP (100) a.UNITFaceDMC, a.identityFaceDMC,  a.VariantID, a.[Index],
CASE WHEN a.identityFaceDMC IN (SELECT identityFaceDMC FROM orig GROUP BY identityFaceDMC HAVING  COUNT(*) > 1) THEN 'Double' ELSE 'Single' END AS UNIT_Identifier,
CASE WHEN a.[Index] = 'A' THEN delay_UNIT ELSE NULL END AS [Delay Btw UNIT_MM A&B (s)],
CASE WHEN a.[Index] = 'A' THEN delay_wrap ELSE NULL END AS [Delay Btw UNIT_Wrap 1&2 (s)],
CASE WHEN a.[Index] = 'A' THEN delay_Push ELSE NULL END AS [Delay Btw UNIT_Push A&B (s)], 
a.UNITMeanTimeDiam,

CASE WHEN UNITMeanTimeDiam < Time THEN 'True' ELSE 'False' END AS UNITMM_TimeCreated_Invstgtn,
a.Time,
a.WrappingTimeDiam, a.PushTimeDiam, a.DateTimeCompleted,
DATEDIFF(SECOND, a.Time, a.DateTimeCompleted) AS OperationTime,
a.DB_CycleTime,
DATEDIFF(SECOND, LAG(a.Time, 1) OVER (order by a.Time ), a.Time) AS Cycle,
CASE WHEN  DATEDIFF(SECOND, LAG(a.DateTimeCompleted, 2) OVER (order by a.DateTimeCompleted ),  a.Time) < 0 then 0 else DATEDIFF(SECOND, LAG(a.DateTimeCompleted, 2) OVER (order by a.DateTimeCompleted ),  a.Time  ) end AS Idle,

a.GUMMeanTimeDiam, a.UNITMeanDiam,a.UNITMeanIsPass, a.BeadWeight, a.GUMMeanGap, a.GUMMeanDiam, a.GUMMeanGUM, a.GUMMeanIsPass, a.PushSpringback, a.PushDisplacement, a.PushForce,
a.ShiftNumber, a.FinalIsPass 

FROM orig AS a INNER JOIN
temp AS b ON a.identityFaceDMC = b.identityFaceDMC
ORDER BY a.identityFaceDMC

SQL

Posted 26-Oct-21 3:38am

emperortekky

Updated 26-Oct-21 4:27am

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Member 15329613 26-Oct-21 10:16am

What is the error?

emperortekky 26-Oct-21 10:19am

Error Source: .NetSqlClient Data Provider
Error Message: Invalid column name 'Cycle'
Invalid column name 'Idle'

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Member 15329613 · Answer 1 · 2021-10-26T04:27:00

I see where you have 'AS Cycle' which is creating your column. To use that column you could create a temp table but more likely a faster approach would be to wrap a SELECT statement around what you have and make what you have a derived table.

Here's a simple example:

SQL

SELECT t.field1, x.dynamic_field  -- this comes from the derived table (nested sql)
FROM table1 t
INNER JOIN (
  -- this is essentially your current sql
  SELECT reference_id AS id, CASE WHEN r.field1 = 'Test' THEN r.field2 ELSE r.field1 END AS dynamic_field
  FROM table2 r
) x ON t.id = x.id