Access Query question

[toryee]

I have trouble understanding the following two fields in an Access query and the differnces between them.
Any explanation is appreciated.



1) emp: sum(IIf([employee].[age] = "45", [employee].[salary], 0))
this is a column with 'Expression' under 'Total'


2) Expr1: IIF([employee].[age] = "45", [employee].[salary], 0))
This is a column with 'Group by' under 'Total'

 

[SteveR77]

toryee,

The two fields are using the same criteria but the result of the fields will be different based on what the total line is doing.

For the first field will give me the sum for all employees who are 45 years of age. In the second field you will have the salaries for those employee who are 45.

HTH,

Steve

 

[JonFer]

If these were the only two fields in the query, then you'd get a row for each unique salary for employees aged 45 and then the sum of the salaries for employees aged 45 with that salary. The sum field would just be the salary multiplied by the number of employees with that exact salary.

  emp   expr1
 40000   80000   (assuming 2 employees at 40K)
 30000   30000   (assuming 1 employee at 30K)