NOTE : BuildMaster has Retention Policies which are strongly recommended, rather than manually purging data
That being said, you can use the same strategy to delete from that table that you used for log entries:
BuildMaster 4.2 and earlier:
SELECT TOP 100 * FROM BuildExecution_PlanActionVariableValues
--DELETE BuildExecution_PlanActionVariableValues
WHERE BuildExecution_PlanAction_Id IN
(SELECT BuildExecution_PlanAction_Id
FROM BuildExecution_PlanActions BEPA
INNER JOIN BuildExecutions BE
ON BE.Execution_Id = BEPA.Execution_Id
INNER JOIN Builds B
ON BE.Application_Id = B.Application_Id
AND BE.Release_Number = B.Release_Number
AND BE.Build_Number = B.Build_Number
WHERE B.BuildStatus_Name = 'Rejected')
BuildMaster 4.3 through 4.9:
SELECT TOP 100 * FROM BuildExecution_ActionGroupActionVariableValues
--DELETE BuildExecution_ActionGroupActionVariableValues
WHERE BuildExecution_ActionGroupAction_Id IN
(SELECT BuildExecution_ActionGroupAction_Id
FROM BuildExecution_ActionGroupActions BEAGA
INNER JOIN BuildExecution_DeploymentPlans BDP
ON BEAGA.BuildExecution_DeploymentPlan_Id = BDP.BuildExecution_DeploymentPlan_Id
INNER JOIN BuildExecutions BE
ON BE.Execution_Id = BDP.Execution_Id
INNER JOIN Builds B
ON BE.Application_Id = B.Application_Id
AND BE.Release_Number = B.Release_Number
AND BE.Build_Number = B.Build_Number
WHERE B.BuildStatus_Name = 'Rejected')
