Alias not recognized

I'm attempting to refer to an alias in my SELECT clause (within a stored
procedure).
Basically I'm building a string which I will eventually execute by calling
the "exec" statement on my string.
Within my string, I have 3 columns for my SELECT clause. Here is an
extremely watered down example of what I'm referring to.
e.g.
SELECT (X.price * Y.units) AS alias_one, (W.price * Z.units) AS alias_two,
alias_one - alias_two
FROM W,X,Y,Z
The issue is that my select clause does NOT recognize "alias_one" and
"alias_two" as aliases when I call exec(myString).
Can I possibly refer to these columns by index within the sql or possibly
declare these aliases at the beginning of the procedure so that they will be
recognized?
Any help is appreciated.
PK9How do you refer the to alias in your stored procedure. If you post the
code, we might be able to help.
-oj
"PK9" <PK9@.discussions.microsoft.com> wrote in message
news:98AB1E92-EB82-4155-9DE5-51DEA95CAEEC@.microsoft.com...
> I'm attempting to refer to an alias in my SELECT clause (within a stored
> procedure).
> Basically I'm building a string which I will eventually execute by calling
> the "exec" statement on my string.
> Within my string, I have 3 columns for my SELECT clause. Here is an
> extremely watered down example of what I'm referring to.
> e.g.
> SELECT (X.price * Y.units) AS alias_one, (W.price * Z.units) AS alias_two,
> alias_one - alias_two
> FROM W,X,Y,Z
> The issue is that my select clause does NOT recognize "alias_one" and
> "alias_two" as aliases when I call exec(myString).
> Can I possibly refer to these columns by index within the sql or possibly
> declare these aliases at the beginning of the procedure so that they will
> be
> recognized?
> Any help is appreciated.
> --
> PK9|||This is dynamic SQL creation that uses a cross-tab/pivot, so I'm afraid
posting it may just confuse the issue.
What I end up with at the end of the SQL creation is the following:
'FY 1999' | 'FY 1999 CMP' as two separate columns that are given those
alias' in the stored procedure. Now, I want to say as another column' FY
1999 minus FY 1999 CMP' to give me the difference between the two columns.
Does that help?
"oj" wrote:

> How do you refer the to alias in your stored procedure. If you post the
> code, we might be able to help.
>
> --
> -oj
>
> "PK9" <PK9@.discussions.microsoft.com> wrote in message
> news:98AB1E92-EB82-4155-9DE5-51DEA95CAEEC@.microsoft.com...
>
>|||Can Anyone help me with this?
I'm really stuck right now.
"oj" wrote:

> How do you refer the to alias in your stored procedure. If you post the
> code, we might be able to help.
>
> --
> -oj
>
> "PK9" <PK9@.discussions.microsoft.com> wrote in message
> news:98AB1E92-EB82-4155-9DE5-51DEA95CAEEC@.microsoft.com...
>
>|||You are trying to do something like this:
SELECT (X.price * Y.units) AS alias_one, (W.price * Z.units) AS alias_two,
alias_one - alias_two
FROM W,X,Y,Z
This isn't possible in the SQL language. The whole select list happens at th
e same time, logically.
Here's one way with which you don't have to repeat the expressions:
SELECT alias_one, alias_two, alias_one - alias_two
FROM
(
SELECT (X.price * Y.units) AS alias_one, (W.price * Z.units) AS alias_two,
FROM W,X,Y,Z
) AS d
--
Tibor Karaszi, SQL Server MVP
http://www.karaszi.com/sqlserver/default.asp
http://www.solidqualitylearning.com/
"PK9" <PK9@.discussions.microsoft.com> wrote in message
news:98AB1E92-EB82-4155-9DE5-51DEA95CAEEC@.microsoft.com...
> I'm attempting to refer to an alias in my SELECT clause (within a stored
> procedure).
> Basically I'm building a string which I will eventually execute by calling
> the "exec" statement on my string.
> Within my string, I have 3 columns for my SELECT clause. Here is an
> extremely watered down example of what I'm referring to.
> e.g.
> SELECT (X.price * Y.units) AS alias_one, (W.price * Z.units) AS alias_two,
> alias_one - alias_two
> FROM W,X,Y,Z
> The issue is that my select clause does NOT recognize "alias_one" and
> "alias_two" as aliases when I call exec(myString).
> Can I possibly refer to these columns by index within the sql or possibly
> declare these aliases at the beginning of the procedure so that they will
be
> recognized?
> Any help is appreciated.
> --
> PK9|||dynamic sql for xtab. hmmm...that sounds quite familiar. wait, we have such
a commercial solution (http://rac4sql.net) :-)
anyway, you cannot just add the two aliases because the aliases are
calculated at runtime. what you can do is to derive the first query then use
the aliases. take a look at tibor's comment.
-oj
"PK9" <PK9@.discussions.microsoft.com> wrote in message
news:FD1A0770-2736-49B8-B684-16AE1927EF92@.microsoft.com...
> This is dynamic SQL creation that uses a cross-tab/pivot, so I'm afraid
> posting it may just confuse the issue.
> What I end up with at the end of the SQL creation is the following:
> 'FY 1999' | 'FY 1999 CMP' as two separate columns that are given those
> alias' in the stored procedure. Now, I want to say as another column' FY
> 1999 minus FY 1999 CMP' to give me the difference between the two columns.
> Does that help?
> "oj" wrote:
>|||Yoiu missed some basic ideas in SQL. Here is how a SELECT works in SQL
... at least in theory. Real products will optimize things, but the
code has to produce the same results.
a) Start in the FROM clause and build a working table from all of the
joins, unions, intersections, and whatever other table constructors are
there. The table expression> AS <correlation name> option allows you
give a name to this working table which you then have to use for the
rest of the containing query.
b) Go to the WHERE clause and remove rows that do not pass criteria;
that is, that do not test to TRUE (i.e. reject UNKNOWN and FALSE). The
WHERE clause is applied to the working set in the FROM clause.
c) Go to the optional GROUP BY clause, make groups and reduce each
group to a single row, replacing the original working table with the
new grouped table. The rows of a grouped table must be group
characteristics: (1) a grouping column (2) a statistic about the group
(i.e. aggregate functions) (3) a function or (4) an expression made up
those three items.
d) Go to the optional HAVING clause and apply it against the grouped
working table; if there was no GROUP BY clause, treat the entire table
as one group.
e) Go to the SELECT clause and construct the expressions in the list.
This means that the scalar subqueries, function calls and expressions
in the SELECT are done after all the other clauses are done. The
"AS" operator can also give names to expressions in the SELECT
list. These new names come into existence all at once, but after the
WHERE clause, GROUP BY clause and HAVING clause has been executed; you
cannot use them in the SELECT list or the WHERE clause for that reason.
If there is a SELECT DISTINCT, then redundant duplicate rows are
removed. For purposes of defining a duplicate row, NULLs are treated
as matching (just like in the GROUP BY).
f) Nested query expressions follow the usual scoping rules you would
expect from a block structured language like C, Pascal, Algol, etc.
Namely, the innermost queries can reference columns and tables in the
queries in which they are contained.
g) The ORDER BY clause is part of a cursor, not a query. The result
set is passed to the cursor, which can only see the names in the SELECT
clause list, and the sorting is done there. The ORDER BY clause cannot
have expression in it, or references to other columns because the
result set has been converted into a sequential file structure and that
is what is being sorted.
As you can see, things happen "all at once" in SQL, not "from left to
right" as they would in a sequential file/procedural language model. In
those languages, these two statements produce different results:
READ (a, b, c) FROM File_X;
READ (c, a, b) FROM File_X;
while these two statements return the same data:
SELECT a, b, c FROM Table_X;
SELECT c, a, b FROM Table_X;
Think about what a mess this statement is in the SQL model.
SELECT f(c2) AS c1, f(c1) AS c2 FROM Foobar;
That is why such nonsense is illegal syntax.
And dynamic SQL is considered bad programming, not quite as bad as
cursors, but still not the way to do it.|||Thanks, that's exactly what I was looking for!
"Tibor Karaszi" wrote:

> You are trying to do something like this:
> SELECT (X.price * Y.units) AS alias_one, (W.price * Z.units) AS alias_two,
> alias_one - alias_two
> FROM W,X,Y,Z
>
> This isn't possible in the SQL language. The whole select list happens at
the same time, logically.
> Here's one way with which you don't have to repeat the expressions:
> SELECT alias_one, alias_two, alias_one - alias_two
> FROM
> (
> SELECT (X.price * Y.units) AS alias_one, (W.price * Z.units) AS alias_two,
> FROM W,X,Y,Z
> ) AS d
> --
> Tibor Karaszi, SQL Server MVP
> http://www.karaszi.com/sqlserver/default.asp
> http://www.solidqualitylearning.com/
>
> "PK9" <PK9@.discussions.microsoft.com> wrote in message
> news:98AB1E92-EB82-4155-9DE5-51DEA95CAEEC@.microsoft.com...
>
>sql