Question

I have a query like this:

SELECT Name,  
REPLACE(RTRIM((
                SELECT CAST(Score AS VARCHAR(MAX)) + ' ' 
                FROM 
                    (SELECT Name, Score
                    FROM table
                    WHERE 
                    ---CONDITIONS---
                    ) AS InnerTable             
                WHERE (InnerTable.Name = OuterTable.Name) FOR XML PATH (''))),' ',', ') AS Scores
FROM table AS OuterTable
WHERE 
---CONDITIONS---
GROUP BY Name;

As it can be seen, I am using the same set of conditions to derive the InnerTable and OuterTable. Is there a way to shorten this query? I am asking this because, sometime back, I saw a keyword USING in MySQL that simplified my life using which you can specify a query once and then use its alias for the rest of the query.

Answer 1

You could look at creating a Common Table Expression (CTE). That is your best bet for aliasing a select. Unfortunately I’m not sure how much shoerter it will make your query though it does prevent you from defining the where conditions twice. see below:

with temp as
(
   SELECT Name, Score
   FROM table
   WHERE whatever = 'whatever'
)

SELECT Name,  
REPLACE(RTRIM((
                SELECT CAST(Score AS VARCHAR(MAX)) + ' ' 
                FROM 
                    (SELECT Name, Score
                    FROM temp                    ) AS InnerTable             
                WHERE (InnerTable.Name = OuterTable.Name) FOR XML PATH (''))),' ',', ') AS Scores
FROM temp AS OuterTable
GROUP BY Name;