Is this sql syntax correct?

Question

Can i apply SUM() within an ISNULL().... Consider my following sql server select statement

SELECT e.Emp_Id,e.Identity_No,e.Emp_Name,case WHEN e.SalaryBasis=1 
THEN 'Weekly' ELSE 'Monthly' end as SalaryBasis,e.FixedSalary,
    ISNULL(Adv.Daily_Wage,0) as Advance from Employee as e 
    inner join Designation as d on e.Desig_Id=d.Desig_Id
    Left Outer Join Payroll as Adv on e.Emp_Id=Adv.Emp_Id where e.Is_Deleted=0 

This Statement Works fine.... But when i apply SUM() within an ISNULL()

SELECT e.Emp_Id,e.Identity_No,e.Emp_Name,case WHEN e.SalaryBasis=1 
    THEN 'Weekly' ELSE 'Monthly' end as SalaryBasis,e.FixedSalary,
        ISNULL(SUM(Adv.Daily_Wage),0) as Advance from Employee as e 
        inner join Designation as d on e.Desig_Id=d.Desig_Id
        Left Outer Join Payroll as Adv on e.Emp_Id=Adv.Emp_Id 
        where e.Is_Deleted=0 

I got the error,

Column 'Employee.Emp_Id' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

Any suggestion....

Answer 1

You need to GROUP BY the other columns in the select. Something like

SELECT  e.Emp_Id,
        e.Identity_No,
        e.Emp_Name,
        case 
            WHEN e.SalaryBasis=1  THEN 'Weekly' 
            ELSE 'Monthly' 
        end as SalaryBasis,e.FixedSalary, 
        ISNULL(SUM(Adv.Daily_Wage),0) as Advance 
from    Employee as e  inner join 
        Designation as d on e.Desig_Id=d.Desig_Id Left Outer Join 
        Payroll as Adv on e.Emp_Id=Adv.Emp_Id  
where   e.Is_Deleted=0 
GROUP BY e.Emp_Id, --This section is what you are missing
        e.Identity_No,
        e.Emp_Name,
        case 
            WHEN e.SalaryBasis=1  THEN 'Weekly' 
            ELSE 'Monthly' 
        end,
    e.FixedSalary

Have a look at the definition here

GROUP BY (Transact-SQL)