Sum a column and perform more calculations on the result? [duplicate] - sql

Question

This question already has an answer here:
How to use an Alias in a Calculation for Another Field
(1 answer)
Closed 3 years ago.
In my query below I am counting occurrences in a table based on the Status column. I also want to perform calculations based on the counts I am returning. For example, let's say I want to add 100 to the Snoozed value... how do I do this? Below is what I thought would do it:
SELECT
pu.ID Id, pu.Name Name,
COUNT(*) LeadCount,
SUM(CASE WHEN Status = 'Working' THEN 1 ELSE 0 END) AS Working,
SUM(CASE WHEN Status = 'Uninterested' THEN 1 ELSE 0 END) AS Uninterested,
SUM(CASE WHEN Status = 'Converted' THEN 1 ELSE 0 END) AS Converted,
SUM(CASE WHEN SnoozedId > 0 THEN 1 ELSE 0 END) AS Snoozed,
Snoozed + 100 AS Test
FROM
Prospects p
INNER JOIN
ProspectsUsers pu on p.OwnerId = pu.SalesForceId
WHERE
p.Store = '108'
GROUP BY
pu.Name, pu.Id
ORDER BY
Name
I get this error:
Invalid column name 'Snoozed'.
How can I take the value of the previous SUM statement, add 100 to it, and return it as another column? What I was aiming for is an additional column labeled Test that has the Snooze count + 100.

Answer 1

You can't use one column to create another column in the same way that you are attempting. You have 2 options:
Do the full calculation (as #forpas has mentioned in the comments above)
Use a temp table or table variable to store the data, this way you can get the first 5 columns, and then you can add the last column or you can select from the temp table and do the last column calculations from there.

Answer 2

You can not use an alias as a column reference in the same query. The correct script is:
SELECT
pu.ID Id, pu.Name Name,
COUNT(*) LeadCount,
SUM(CASE WHEN Status = 'Working' THEN 1 ELSE 0 END) AS Working,
SUM(CASE WHEN Status = 'Uninterested' THEN 1 ELSE 0 END) AS Uninterested,
SUM(CASE WHEN Status = 'Converted' THEN 1 ELSE 0 END) AS Converted,
SUM(CASE WHEN SnoozedId > 0 THEN 1 ELSE 0 END)+100 AS Snoozed
FROM
Prospects p
INNER JOIN
ProspectsUsers pu on p.OwnerId = pu.SalesForceId
WHERE
p.Store = '108'
GROUP BY
pu.Name, pu.Id
ORDER BY
Name

Answer 3

MSSQL does not allow you to reference fields (or aliases) in the SELECT statement from within the same SELECT statement.
To work around this:
Use a CTE. Define the columns you want to select from in the CTE, and then select from them outside the CTE.
;WITH OurCte AS (
SELECT
5 + 5 - 3 AS OurInitialValue
)
SELECT
OurInitialValue / 2 AS OurFinalValue
FROM OurCte
Use a temp table. This is very similar in functionality to using a CTE, however, it does have different performance implications.
SELECT
5 + 5 - 3 AS OurInitialValue
INTO #OurTempTable
SELECT
OurInitialValue / 2 AS OurFinalValue
FROM #OurTempTable
Use a subquery. This tends to be more difficult to read than the above. I'm not certain what the advantage is to this - maybe someone in the comments can enlighten me.
SELECT
5 + 5 - 3 AS OurInitialValue
FROM (
SELECT
OurInitialValue / 2 AS OurFinalValue
) OurSubquery
Embed your calculations. opinion warning This is really sloppy, and not a great approach as you end up having to duplicate code, and can easily throw columns out-of-sync if you update the calculation in one location and not the other.
SELECT
5 + 5 - 3 AS OurInitialValue
, (5 + 5 - 3) / 2 AS OurFinalValue

Answer 4

You can't use a column alias in the same select. The column alias do not precedence / sequence; they are all created after the eval of the select result, just before group by and order by.
You must repeat code :
SELECT
pu.ID Id,pu.Name Name,
COUNT(*) LeadCount,
SUM(CASE WHEN Status = 'Working' THEN 1 ELSE 0 END) AS Working,
SUM(CASE WHEN Status = 'Uninterested' THEN 1 ELSE 0 END) AS Uninterested,
SUM(CASE WHEN Status = 'Converted' THEN 1 ELSE 0 END) AS Converted,
SUM(CASE WHEN SnoozedId > 0 THEN 1 ELSE 0 END) AS Snoozed,
SUM(CASE WHEN SnoozedId > 0 THEN 1 ELSE 0 END)+ 100 AS Test
FROM
Prospects p
INNER JOIN
ProspectsUsers pu on p.OwnerId = pu.SalesForceId
WHERE
p.Store = '108'
GROUP BY
pu.Name, pu.Id
ORDER BY
Name
If you don't want to repeat the code, use a subquery
SELECT
ID, Name, LeadCount, Working, Uninterested,Converted, Snoozed, Snoozed +100 AS test
FROM
(SELECT
pu.ID Id,pu.Name Name,
COUNT(*) LeadCount,
SUM(CASE WHEN Status = 'Working' THEN 1 ELSE 0 END) AS Working,
SUM(CASE WHEN Status = 'Uninterested' THEN 1 ELSE 0 END) AS Uninterested,
SUM(CASE WHEN Status = 'Converted' THEN 1 ELSE 0 END) AS Converted,
SUM(CASE WHEN SnoozedId > 0 THEN 1 ELSE 0 END) AS Snoozed
FROM Prospects p
INNER JOIN ProspectsUsers pu on p.OwnerId = pu.SalesForceId
WHERE p.Store = '108'
GROUP BY pu.Name, pu.Id) t
ORDER BY Name
or a view