SQL Server: when Else is case it is showing 0 as default in CASE clause

Question

This query is run on AdventureWorks2014.Sales.SalesOrderDetail table.

My query: in the CASE clause I have clearly stated to show - when it is the ELSE case. This query removes the repeating SalesOrderID and after 1st time shown it should be replaced with "-" this character.

SELECT 
    CASE WHEN ROW_NUMBER() OVER(PARTITION BY SalesOrderID ORDER BY SalesOrderID ASC) = 1 THEN SalesOrderID ELSE '-' END  AS SalesOrderID,
    R.ProductID,
    R.OrderQty,
    R.UnitPrice,
    R.LineTotal

FROM AdventureWorks2014.Sales.SalesOrderDetail AS R

currently showing 0 even though i said in the ELSE to show me -

Answer 1

Below query will solve your issue

 SELECT 
        CASE WHEN ROW_NUMBER() OVER(PARTITION BY SalesOrderID ORDER BY SalesOrderID ASC) = 1 THEN CONVERT(varchar(10),SalesOrderID) ELSE '-' END  AS SalesOrderID,
        R.ProductID,
        R.OrderQty,
        R.UnitPrice,
        R.LineTotal

    FROM AdventureWorks2014.Sales.SalesOrderDetail AS R