SQL LIMIT 1 DESC order

Question

I am trying to show only the highest selling product per work center, however, it keeps telling me that LIMIT 1 is the incorrect syntax. I cant seem to find an answer on here that has helped so I decided to ask the question. Here's my query.

SELECT WorkCenter.WorkCenterCode, Product.Name, SUM(CustomerOrderLine.Quantity*CustomerOrderLine.ActualPrice) AS 'Total Sales'
FROM WorkCenter 
    INNER JOIN Product ON WorkCenter.WorkCenterCode = Product.WorkCenterCode 
    INNER JOIN CustomerOrderLine ON Product.ProductID = CustomerOrderLine.ProductID
    GROUP BY WorkCenter.WorkCenterCode, Product.Name
    ORDER BY 'Total Sales' DESC 
    LIMIT 1

Answer 1

Here is your query cleaned up a bit:

SELECT  wc.WorkCenterCode, p.Name, SUM(col.Quantity*col.ActualPrice) AS "Total Sales"
FROM WorkCenter wc INNER JOIN
     Product p
     ON wc.WorkCenterCode = p.WorkCenterCode INNER JOIN
     CustomerOrderLine col
     ON p.ProductID = col.ProductID
GROUP BY wc.WorkCenterCode, p.Name
ORDER BY "Total Sales" DESC
LIMIT 1

Note the important change from double quotes to single quotes. This is especially important for the order by clause so the clause actually does something, rather than sorting by a constant. The addition of table aliases makes the query easier to read.

If you are using Visual Studio, you should use top rather than limit:

SELECT TOP 1 wc.WorkCenterCode, p.Name, SUM(col.Quantity*col.ActualPrice) AS "Total Sales"
FROM WorkCenter wc INNER JOIN
     Product p
     ON wc.WorkCenterCode = p.WorkCenterCode INNER JOIN
     CustomerOrderLine col
     ON p.ProductID = col.ProductID
GROUP BY wc.WorkCenterCode, p.Name
ORDER BY "Total Sales" DESC;

EDIT:

For one row per work center, use this as a subquery with row_number():

SELECT WorkCenterCode, Name, "Total Sales"
FROM (SELECT wc.WorkCenterCode, p.Name, SUM(col.Quantity*col.ActualPrice) AS "Total Sales",
             row_number() over (partition by wc.WorkCenterCode order by SUM(col.Quantity*col.ActualPrice) desc) as seqnum
      FROM WorkCenter wc INNER JOIN
           Product p
           ON wc.WorkCenterCode = p.WorkCenterCode INNER JOIN
           CustomerOrderLine col
           ON p.ProductID = col.ProductID
      GROUP BY wc.WorkCenterCode, p.Name
     ) t
WHERE seqnum = 1
ORDER BY "Total Sales" DESC;

Answer 2

For SQL Server use SELECT TOP 1

SELECT TOP 1 WorkCenter.WorkCenterCode, Product.Name, SUM(CustomerOrderLine.Quantity*CustomerOrderLine.ActualPrice) AS [Total Sales]
FROM            WorkCenter INNER JOIN
                     Product ON WorkCenter.WorkCenterCode = Product.WorkCenterCode INNER     JOIN
                     CustomerOrderLine ON Product.ProductID = CustomerOrderLine.ProductID
GROUP BY WorkCenter.WorkCenterCode, Product.Name
ORDER BY [Total Sales] DESC 

Answer 3

Here's another SO question on the topic which uses ROW_NUMBER(). TOP 1 will only return one row in total whereas ROW_NUMER() can return one row per group.