db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Laura Stewart" <scotsmat...@gmail.com>
Subject Need help on ORDER BY with expressions
Date Fri, 16 Feb 2007 21:32:05 GMT
The JIRA issue DERBY-264 is for documenting the updates to the ORDER
BY clause which allows expressions ( DERBY-134 ).  The comments on
DERBY-264 show some examples, but I need additional help understanding
what needs to be documented:

1. The type of expressions that are allowed. My impression is that
they are the Boolean expressions (as opposed to TableExpressions or
SelectExpressions)?

2. I need to understand how the Syntax for ORDER BY should appear.
Should it just be "Expressions" added immediately after ColumnPosition
(in both places in the Syntax? Or should it be specific type of
expression (TableExpression, SelectExpression, Boolean Expression).
Are there limitations as to the types of expressions allowed? Boolean,
concatenation?

3. Description of the expressions allowed (will appear below the
syntax) This will depend on what type of expressions are allowed, but
one thing that the other parameters mention is if the column needs to
be in the select list. I need help describing the expressions
parameter.

4. Whatever type of expressions are allowed, that topic in the Derby
Ref Guide needs to be updated too. Are there any limitations for ORDER
BY? For example, the Boolean expressions topic mentions that there are
limitations with check constraints.

Thanks!

-- 
Laura Stewart

Mime
View raw message