Pass by reference vs. pass by value

This one is for myself, as I often forget how to implement pass by reference and pass by value, and what the difference is between them.
Pass by reference:

Declare varible and set it :
SalesLine salesLine = salesLine4

Down-side is if salesLine4 changes - so does salesLine

Pass by value:

SalesLine salesLine;
salesLine.data(salesLine4);

Happy ax-hacking

If salesLine4 changes - salesLine doesn't

Deleting duplicate records in SQL

Recently I needed to delete some duplicate records across several companies in AX. The table is self-contained so I needn't worry about delete actions or validation and as there are several companies I wanted to try and do it SQL-style. So this is what I came up with

DELETE FROM [Table with Duplicates]
WHERE [Primary Key Field] IN
DELETE FROM [Table with Duplicates]
WHERE [Primary Key Field] IN
(
SELECT a.[Primary Key Field]
FROM [Table with Duplicates] a,
[Table with Duplicates] b

WHERE a.[Primary Key Field]!= b.[Primary Key Field] -- i.e. Userkey
AND a.[Value to check]= b.[Value to Check] -- i.e. Lastname
AND a.[Second Value to Check] = b.[Second Value to Check] -- i.e. Firstname
AND a.[Primary Key Field] < b.[Primary Key Field] -- i.e. Userkey
)

Respect to the original poster at SQL Server forum.

Remember always to backup your data and try the SQL-statement on a test table before you do anything on data which will be used in live environments.