hi,please help i want to get the sum of Cp=((partlist.usl-partlist.lsl)/(6*stdev(spcdata.data))SELECT SpcData.PartNo, SpcData.Dimension, SpcData.MachineNo, SUM(SpcData.SampleNo / 5) AS subgroup, STDEV(SpcData.Data) AS stdevdata, PartList.USL, PartList.LSL, SUM((PartList.USL - PartList.LSL) / (6 * STDEV(SpcData.Data) AS stdevdata))) AS cpFROM SpcData INNER JOIN PartList ON SpcData.PartNo = PartList.PartNo AND SpcData.Dimension = PartList.DimensionGROUP BY SpcData.PartNo, SpcData.Dimension, SpcData.MachineNo, PartList.USL, PartList.LSL
please help how to get the correct query result.thanks.