Replace NULL before Inserting into File ?

[MFisher]

I am modifying a QRPGLESRC program with embedded SQL. It's inserting into a file that doesn't allow NULLs. What is the IBMi equivalent of ISNULL to check for a null value, so I can replace with a 0 or blank ?

EDIT: Looks like IFNULL is what I want

[Scott M]

I use COALESCE().

[B.Hauser]

COALESCE and IFNULL convert both a NULL value into a default value, but COALESCE is more powerful, because we can specify multiple option, while IFNULL must be nested.
Example:

Select Coalesce(a.CustNo, b.CustNo, c.CustNo) Customer1,
       IFNull(IFNull(a.CustNo, B.CustNo), c.CustNo) Customer2  
      .....
   from Sales2018 a full join Sales2019 b on a.CustNo = b.CustNo
                    full join Sales2020 c on a.CustNo = c.CustNo
   .....

Birgitta