How to design T-SQL query to calculate sum in one pass? - tsql

Question

I am trying to develop a T-SQL query which will do the following:
ROUND(100 * A / B, 1)
Simple in concept, but it's tricky because of possible B=0 denominator and also because of A and B variables. What I expect is a percent value like 93.2 (given in this format without %). Or even 932 would be acceptable since I could convert it later.
But instead, I'm currently getting 151, which is the number of records.
A = CASE WHEN A.MFG IS NULL AND A.MFG2 IS NULL AND A.QC IS NULL AND A.QC2 IS NULL THEN 1 ELSE 0 END
B = CASE WHEN [Date_Completed] IS NOT NULL THEN 1 ELSE 0 END
My current logic only divides A/B if B is not equal to zero. Can you please help me fix this? p.s. all fields above are from the same table A.
I tried:
SELECT CASE WHEN t.VarB<>0 THEN ROUND(100 * t.VarA / t.VarB, 1)
ELSE 0 /* or whatever you'd want to return in this case */
END
FROM (SELECT CASE WHEN A.MFG IS NULL AND A.MFG2 IS NULL AND A.QC IS NULL AND A.QC2 IS NULL THEN 1
ELSE 0
END AS VarA,
CASE WHEN [Date_Completed] IS NOT NULL THEN 1
ELSE 0
END AS VarB
FROM EXCEL.Batch_Records A) t
But I got 33000 rows returned instead of just one, where each row = 100 or 0.
Good idea, Conrad! I tested your solution and it works if I just want that one value. But what I didn't tell you was that there are additional values I need returned from same query. When I tried adding in the other value calculations, I got syntax errors. So here is my current query. How should htis be rewritten please?
select
SUM(CASE WHEN A.DATE_RECEIVED IS NOT NULL THEN 1 ELSE 0 END) AS NUM_RECEIVED,
SUM(CASE WHEN [Date_Completed] IS NOT NULL THEN 1 ELSE 0 END) AS NUM_COMPLETE_OF_OPENED,
SUM(CASE WHEN A.DATE_COMPLETED IS NOT NULL THEN 1 ELSE 0 END) AS NUM_COMPLETED_IN_MONTH,
SUM(CASE WHEN A.MFG IS NULL AND A.MFG2 IS NULL AND A.QC IS NULL AND A.QC2 IS NULL THEN 1 ELSE 0 END) AS NUM_WITHOUT_ERROR,
round(100 * a/b , 1)
from
(select
sum(CASE
WHEN A.MFG IS NULL AND A.MFG2 IS NULL AND A.QC IS NULL AND A.QC2 IS NULL THEN
1.0
ELSE 0.0 END) A,
sum(CASE WHEN [Date_Completed] IS NOT NULL THEN
1.0 ELSE 0.0 END) B
FROM EXCEL.Batch_Records a
LEFT JOIN EXCEL.QC_CODES d ON a.Part_Number = d.CODE_ID
WHERE (a.[Group] = #GROUP or #GROUP = '' OR #GROUP IS NULL) AND A.Date_Received >= #STARTDATE AND A.Date_Received <= #ENDDATE
Conrad correctly advised me that #TEMP1 was an empty table. But now I populated it and successfully designed this query with his help:
SET #STARTDATE = '1/1/11'
SET #ENDDATE = '1/31/11'
SET #GROUP = 'INTERMEDIATES_FISH'
--SET #TABLE_TITLE = 'BATCH RECORD SUCCESS RATE'
--SET #DEPT = 'QC'
IF EXISTS(SELECT * FROM TEMPDB.INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME LIKE '#TEMP1%')
DROP TABLE #TEMP1
--CREATE TABLE #TEMP1 ( MFG int , MFG2 int , QC int, QC2 INT , [Group] NVARCHAR(MAX), [Date_Completed] datetime, Date_Received datetime)
SELECT
MFG, MFG2, QC, QC2, [GROUP], [DATE_COMPLETED], [DATE_RECEIVED]
INTO #TEMP1
FROM EXCEL.Batch_Records a
WHERE (a.[Group] = #GROUP or #GROUP = '' OR #GROUP IS NULL) AND A.Date_Received >= #STARTDATE AND A.Date_Received <= #ENDDATE
------------------------------------------
;WITH CTE AS
(
SELECT
CASE
WHEN A.MFG IS NULL AND A.MFG2 IS NULL AND A.QC IS NULL AND A.QC2 IS NULL THEN
1.0
ELSE 0.0 END A,
CASE WHEN [Date_Completed] IS NOT NULL THEN 1.0 ELSE 0.0 END B,
CASE WHEN A.Date_Received IS NOT NULL THEN 1 ELSE 0 END NUM_RECEIVED,
CASE WHEN [Date_Completed] IS NOT NULL THEN 1 ELSE 0 END NUM_COMPLETE_OF_OPENED,
CASE WHEN A.DATE_COMPLETED IS NOT NULL THEN 1 ELSE 0 END NUM_COMPLETED_IN_MONTH,
CASE WHEN A.MFG IS NULL AND A.MFG2 IS NULL AND A.QC IS NULL AND A.QC2 IS NULL THEN 1 ELSE 0 END AS NUM_WITHOUT_ERROR
FROM
#TEMP1 a
--WHERE (a.[Group] = #GROUP or #GROUP = '' OR #GROUP IS NULL) AND A.Date_Received >= #STARTDATE AND A.Date_Received <= #ENDDATE
)
select
round(100 * SUM(A)/SUM(b) , 1) ,
SUM(NUM_RECEIVED) NUM_RECEIVED,
SUM(NUM_COMPLETE_OF_OPENED) NUM_COMPLETE_OF_OPENED,
SUM(NUM_COMPLETED_IN_MONTH) NUM_COMPLETED_IN_MONTH,
SUM(NUM_WITHOUT_ERROR) NUM_WITHOUT_ERROR
FROM CTE

Answer 1

Basically you need to use SUM() to get the sum. You should also use 1.0 and 0.0 so you get decimal values.
You should also do the SUM before the Division
UPDATE
Since you're adding in a number of SUM(CASE statements its probably more readable to move the CASE statments out to a CTE.
CREATE TABLE #Batch_Records (
MFG int ,
MFG2 int ,
QC int,
QC2 INT ,
[Group] int,
[Date_Completed] datetime,
Date_Received datetime)
INSERT INTO #Batch_Records (MFG , MFG2 , QC , QC2 , [Group] , [Date_Completed] , Date_Received )
VALUES (1,null,null,null,1,'1/4/2011','2/4/2011'),
(null,null,null,null,1,'2/2/2011','3/4/2011'),
(1,null,null,null,1,'3/6/2011','4/3/2011'),
(null,null,null,null,1,NULL,'5/4/2011'),
(1,null,null,null,1,'5/4/2011','6/6/2011'),
(1,null,null,null,1,NULL,'7/4/2011')
DECLARE #GROUP int
DECLARE #STARTDATE DateTime
DECLARE #ENDDATE DateTime
SET #GROUP = 1
SET #STARTDATE = '1/1/2001'
SET #ENDDATE = '1/1/2012'
;WITH CTE AS
(
SELECT
CASE
WHEN A.MFG IS NULL AND A.MFG2 IS NULL AND A.QC IS NULL AND A.QC2 IS NULL THEN
1.0
ELSE 0.0 END A,
CASE WHEN [Date_Completed] IS NOT NULL THEN
1.0 ELSE 0.0 END B,
CASE WHEN A.Date_Received IS NOT NULL THEN 1 ELSE 0 END NUM_RECEIVED,
CASE WHEN [Date_Completed] IS NOT NULL THEN 1 ELSE 0 END NUM_COMPLETE_OF_OPENED,
CASE WHEN A.DATE_COMPLETED IS NOT NULL THEN 1 ELSE 0 END NUM_COMPLETED_IN_MONTH,
CASE WHEN A.MFG IS NULL AND A.MFG2 IS NULL AND A.QC IS NULL AND A.QC2 IS NULL THEN 1 ELSE 0 END AS NUM_WITHOUT_ERROR
FROM
#Batch_Records a
WHERE
(a.[Group] = #GROUP or #GROUP = '' OR #GROUP IS NULL)
AND A.Date_Received >= #STARTDATE AND A.Date_Received <= #ENDDATE
)
select
round(100 * SUM(A)/SUM(b) , 1) ,
SUM(NUM_RECEIVED) NUM_RECEIVED,
SUM(NUM_COMPLETE_OF_OPENED) NUM_COMPLETE_OF_OPENED,
SUM(NUM_COMPLETED_IN_MONTH) NUM_COMPLETED_IN_MONTH,
SUM(NUM_WITHOUT_ERROR) NUM_WITHOUT_ERROR
FROM CTE
DROP TABLE #Batch_Records