MS-Access -> SELECT AS + ORDER BY = error

问题

I'm trying to make a query to retrieve the region which got the most sales for sweet products. 'grupo_produto' is the product type, and 'regiao' is the region. So I got this query:

SELECT TOP 1 r.nm_regiao,  (SELECT COUNT(*)
        FROM Dw_Empresa
        WHERE grupo_produto='1' AND 
        cod_regiao = d.cod_regiao) as total 
FROM Dw_Empresa d
INNER JOIN tb_regiao r ON r.cod_regiao = d.cod_regiao ORDER BY total DESC

Then when i run the query, MS-Access asks for the "total" parameter. Why it doesn't consider the newly created 'column' I made in the select clause?

Thanks in advance!

回答1:

Aliases are only usable in the query output. You can't use them in other parts of the query. Unfortunately, you'll have to copy and paste the entire subquery to make it work.

回答2:

Old Question I know, but it may help someone knowing than while you cant order by aliases, you can order by column index. For example, this will work without error :

SELECT 
 firstColumn,
 IIF(secondColumn = '', thirdColumn, secondColumn) As yourAlias
FROM
 yourTable
ORDER BY
 2 ASC

The results would then be ordered by the values found in the second column wich is the Alias "yourAlias".

回答3:

You can do it like this

select * from(
  select a + b as c, * from table)
  order by c

Access has some differences compared to Sql Server.

回答4:

Why it doesn't consider the newly created 'column' I made in the select clause?

Because Access (ACE/Jet) is not compliant with the SQL-92 Standard.

Consider this example, which is valid SQL-92:

SELECT a AS x, c - b AS y
  FROM MyTable
 ORDER
    BY x, y;

In fact, x and y the only valid elements in the ORDER BY clause because all others are out of scope (ordinal numbers of columns in the SELECT clause are valid though their use id deprecated).

However, Access chokes on the above syntax. The equivalent Access syntax is this:

SELECT a AS x, c - b AS y
  FROM MyTable
 ORDER
    BY a, c - b;

However, I understand from @Remou's comments that a subquery in the ORDER BY clause is invalid in Access.

回答5:

Try using a subquery and order the results in an outer query.

SELECT TOP 1 * FROM
(
    SELECT
        r.nm_regiao, 
        (SELECT COUNT(*)
         FROM Dw_Empresa
         WHERE grupo_produto='1' AND cod_regiao = d.cod_regiao) as total 
    FROM Dw_Empresa d
    INNER JOIN tb_regiao r ON r.cod_regiao = d.cod_regiao
) T1
ORDER BY total DESC

(Not tested.)

回答6:

How about:

SELECT TOP 1  r.nm_regiao 
FROM (SELECT Dw_Empresa.cod_regiao, 
             Count(Dw_Empresa.cod_regiao) AS CountOfcod_regiao
      FROM Dw_Empresa
      WHERE Dw_Empresa.[grupo_produto]='1'
      GROUP BY Dw_Empresa.cod_regiao
      ORDER BY Count(Dw_Empresa.cod_regiao) DESC) d
INNER JOIN tb_regiao AS r 
ON d.cod_regiao = r.cod_regiao

回答7:

I suggest using an intermediate query.

 SELECT r.nm_regiao, d.grupo_produto, COUNT(*) AS total
   FROM Dw_Empresa d INNER JOIN tb_regiao r ON r.cod_regiao = d.cod_regiao
   GROUP BY r.nm_regiao, d.grupo_produto;

If you call that GroupTotalsByRegion, you can then do:

SELECT TOP 1 nm_regiao, total FROM GroupTotalsByRegion 
  WHERE grupo_produto = '1' ORDER BY total DESC

You may think it's extra work to create the intermediate query (and, in a sense, it is), but you will also find that many of your other queries will be based off of GroupTotalsByRegion. You want to avoid repeating that logic in many other queries. By keeping it in one view, you provide a simplified route to answering many other questions.

来源：https://stackoverflow.com/questions/3953822/ms-access-select-as-order-by-error

标签

sql

ms-access

select

sql-order-by