条件级联T-SQL

Question

I have observed a kind of similar question T SQL Conditional String Concatenation but stil can't get my hear around how to do this., I can't even figure out where to start.

My query so far looks like this:

SELECT
    R.ReservationsID 'Job No',
    C.[Trading Name]'Customer Name',
    C.[Business Address1] 'Customer Address1',
    C.[Business Address2]'Customer Address2',
    C.[Business Town]'Customer Town',
    C.[Business Postal Code]'Customer Postcode',
    C.CustomerID' Customer ID',
    I.InvoiceID' InvoiceID' ,
    'address' AS [Supplier Address 1], --CHANGE
    'address' AS [Supplier Address 2], --CHANGE
    'town' AS [town], --CHANGE
    'post code' AS [Post Code], --CHANGE
    'Supplier' AS [Supplier], --CHANGE
    R.Quantity 'Purchase QTY',
    SM.Instock 'QTY In Stock',
    SM.StockCode 'Product Code',
    SM.StockDescription 'Sale Unit',
    R.[Delivery Date],
    V.[Registration]'Vehicle Reg',
    I.[NET] 'Sale Price',
    I.[GROSS] 'Total Sale Price',
    R.[Delivery Date] ' Del Date',
    R.Quantity as qty,  --CHANGE
    SM.StockDescription AS [Purchase Unit],  --CHANGE
    0.0 AS [Purchase total price],  --CHANGE
    0.0 AS [PO No],
    (D.Forename + ' ' + D.Surname) AS [Driver Name],
    (convert(varchar(10),dateadd(MM,-7,GETDATE()),103)) AS 'Date -7 Months',
    0.0 AS [Purchase Invoice],
    0.0 AS [Purchase Price],
    RI.StockID
FROM  
    dbo.tblReservation R
    LEFT JOIN tblReservationItems RI 
        ON RI.ReservationsID = R.ReservationsID 
            AND (RI.Deleted != 1) AND (R.Completed !=0)
    LEFT JOIN tblInvoice I ON I.InvoiceID = R.Invoice AND (I.Deleted != 1) 
    LEFT JOIN tblCustomer C ON C.CustomerID = R.CustomerID 
    LEFT JOIN tblStockMaster SM ON SM.StockID = RI.StockID
    LEFT JOIN dbo.tblvehicle V ON v.VehicleID = R.VehicleID
    LEFT JOIN dbo.tblDriver D ON D.DriverID = R.DriverID
WHERE      (I.Deleted = 0)
    AND (r.completed=1)
    AND [Delivery Date] >= DATEADD(month, -7, GETDATE())
    AND [Delivery Date] IS NOT NULL

The report is based around R.ReservationsID 'Job No' However there can be multiple "Sale Units" and "Purchase Units" to each "Job No" so what I am trying to do is concatenate the various "purchase units" and "Sale units" into 1 single column separated by commas to align with the "Job Number".

To confuse this even more I would also like to concat the QTY of Purchase Units & Sale Unit's into the column so it would look a little like this.

Desired Output:

New_Concat_Column

[QTY] + 'x' + [SALE UNIT] + ","[QTY] + 'x' + [SALE UNIT] + ","

Any pointers about how to go about this would be greatly appreciated. It would be good to do this in pure SQL but any methods in Crystal Reports are also welcome.

Answer 1

You need to use CAST or CONVERT to change the numeric data to strings:

Cast( R.Quantity as VarChar(10) ) + 'x' + SM.StockDescription + ', ' +
  Cast( R.Quantity as VarChar(10) ) + 'x' + SM.StockDescription  + ',' as New_Concat_Column

Aside: It is often helpful to tag database questions with the database software and version, eg SQL Server 2008R2, and to include applicable table schemas. I have assumed that Sale Unit is a string of some sort.