Ms-access – ORDER BY clause with Alias

aliasms accessorder-by

I am trying to get the sum of the market values for each given CPTY. Each CPTY can have several market values. In my output list, i want to see the top 5 CPTYs, ordered by the sum of their market values.

Works:

SELECT TOP 5 CPTY, SUM( MKT_VAL ) AS MarketVal
FROM Eod
GROUP BY CPTY
ORDER BY SUM( MKT_VAL ) DESC;

Fails:

SELECT TOP 5 CPTY, SUM( MKT_VAL ) AS MarketVal
FROM Eod
GROUP BY CPTY
ORDER BY MarketVal DESC;

It appears when I try to ORDER BY the Alias (MarketVal), Access asks for MarketVal parameter value. However, when I ORDER BY SUM( MKT_VAL ), the code executes fine. I can't understand why this is, can anyone tell me why?

Best Answer

There is no issue in both the query they will run properly.

you must inspect any expressions Or find the identifier that is causing this.

Related Solutions

Mysql – How to make MySQL auto increment in random order

Here's what I would do. I hope I did understand your question correctly. It's a workaround and perhaps not very elegant:

create a random field, and then an AUTO_INCREMENT field ("ID") as the single field of a primary key, order by RND etc
create a temporary table with MIN(ID) for each combination of Col1/2 (first, but randomly):


SELECT
  MIN(ID) AS MIN_ID, Col1, Col2 
FROM 
  table 
GROUP BY 
 Col1, Col2

add a second INT field to be the first_index
update the table and set first_index to be the difference between the minimum value and the running value of the autoincremented field:


UPDATE 
  table t, temp_table tmp
SET 
  t.first_index = (t.ID - tmp.MIN_ID) + 1
WHERE 
  t.Col1=tmp.Col1 AND t.Col2=tmp.Col2

optionally remove the random and ID field, and add a new PK with the three fields Col1/Col2/first_index (auto incremented) for following inserts

MySQL Performance – Indexes Not Used When Joining Tables

What about this this should remove the need for an "Using temporary; Using filesort" because the data is in the right sort already.

You need to know the trick why MySQL needs "Using temporary; Using filesort" to remove that need.

See second sqlfriddle for an explain about removing the need

SELECT
      *
    FROM base_article

    STRAIGHT_JOIN 
      mag_article
    ON
      (mag_article.basearticle_ptr_id = base_article.id)

    WHERE
      base_article.is_published = 1

    ORDER BY
      base_article.date_published DESC

see http://sqlfiddle.com/#!2/302710/2

Works pretty good i needed this also some time ago for Country / city tables see demo here with example data http://sqlfiddle.com/#!2/b34870/41

Edited you also may want to analyse this answer if base_article.is_published = 1 always returns 1 record like your explain explained an INNER JOIN deliverd table may give better performance like the queries in the answer below

https://stackoverflow.com/questions/18738483/mysql-slow-query-using-filesort/18774937#18774937

Best Answer

Related Solutions

Mysql – How to make MySQL auto increment in random order

MySQL Performance – Indexes Not Used When Joining Tables

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