Re: [Hsqldb-developers] Funny SELECT Question

[John Y. <joh...@gm...>]

Hello Clayton,

The HSQLDB has a number of built-in functions. Please check out the
documentation. It seems like you need one of two functions:

IFNULL(exp,value)

if exp is null, value is returned else exp)

COALESCE(expr1,expr2,expr3,...)[2<http://hsqldb.org/doc/guide/ch09.html#ftn.posthyper>
]

if expr1 is not null then it is returned else, expr2 is evaluated and if not
null it is returned and so on
John

On Jan 11, 2008 12:10 PM, Clayton Carter <crc...@gm...> wrote:

> Being a little new to SQL, I have a question that I'm having a hard
> time answering.  I have created a master/detail desktop application
> using HSQL to handle farm and garden crop planning.  Since a number of
> different crops might have very similar characteristics and only vary
> in a few details, I wanted to implement some form of "data
> inheritance" where a database record (record A) could be marked as
> being similar to another record (record B) and any blank fields in the
> record A could be filled in with data from the corresponding fields in
> record B.
>
> I have gotten this to work great in the logic of my program, which is
> to say that the data structures I've created to hold and handle
> individual records are able to work with this inheritance scheme quite
> well.  My current problem is that the "master" list or table that is
> displayed (which is just a Java TableModel wrapped around a ResultSet)
> is riddled with blank cells that I would like to fill in
> automatically.
>
> Any suggestions on how to create a SELECT statement that automatically
> fills in blank or NULL values with the corresponding values from
> another record?
>
> Thanks!
>
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-- 
John Yeary
--
"If I have seen further, it is because I have stood on the shoulders of
giants..."  Sir Isaac Newton