First - works:

SELECT
JobType,
SUM(Qty) AS "Total Units",
COALESCE((SELECT SUM(X.Qty) FROM JobTickets X WHERE X.JobType = JobTickets.JobType AND X.JobCode = 'SVC' RANGE 1 TO 1),0) AS Bounces,
CAST(
100*
(SELECT COALESCE(SUM(P.Qty),0) FROM JobTickets P WHERE P.JobType = JobTickets.JobType AND P.JobCode = 'SVC' )
/
(SELECT COALESCE(SUM(Qty),0) FROM JobTickets  Q WHERE Q.JobType = JobTickets.JobType )
AS NUMERIC(5,2)) AS Pcnt
FROM JobTickets
GROUP BY JobType

Second - doesn't:

SELECT
JobType,
SUM(Qty) AS "Total Units",
COALESCE((SELECT SUM(X.Qty) FROM JobTickets X WHERE X.JobType = JobTickets.JobType AND X.JobCode = 'SVC' RANGE 1 TO 1),0) AS Bounces,
CAST(
100*
(SELECT COALESCE(SUM(P.Qty),0) FROM JobTickets P WHERE P.JobType = JobTickets.JobType AND P.JobCode = 'SVC' )
/
SUM(Qty)  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
AS NUMERIC(5,2)) AS Pcnt
FROM JobTickets
GROUP BY JobType

---

 Comments and Workarounds

---

The problem was that the sub-query was not getting broken out as a separate sub-expression for the SELECT column, thus resulting in the sub-query getting evaluated *again* during the *result row evaluation* where the final SELECT column expressions are evaluated.

---

 Resolution

---

Fixed Problem on 10/23/2018 in version 2.29 build 1

---

 Products Affected

---

ElevateDB Additional Software and Utilities
ElevateDB DAC Client-Server
ElevateDB DAC Client-Server with Source
ElevateDB DAC Standard
ElevateDB DAC Standard with Source
ElevateDB DAC Trial
ElevateDB LCL Standard with Source
ElevateDB PHP Standard
ElevateDB PHP Standard with Source
ElevateDB PHP Trial
ElevateDB VCL Client-Server
ElevateDB VCL Client-Server with Source
ElevateDB VCL Standard
ElevateDB VCL Standard with Source
ElevateDB VCL Trial