I have a BAQ with a subquery with the expression

```
sum(JobMtl.TotalCost/JobHead.ProdQty)
```

The displayed fields are:

So what exactly is going on to calculate the Calculated_MtlCost field?

I assume the Group by By on Company and JobNum limit the sum to records with common values for those fields.

Anyway … I’m running into when this BAQ is run when a Job is created, but no demand added (ie. no Prod Qty). Which gives me a div by zero error.

Can an expression like

```
sum(JobMtl.TotalCost/(case when JobHead.ProdQty = 0 then 1 else JobHead.ProdQty end))
```

be used?

In embedded programming (where most decimals were rounded anyway), I’d just us

```
sum(JobMtl.TotalCost / (JobHead.ProdQty+ 0.0000001) )
```