SQL WHERE IN from param or variable - sql

Question

Context
We are currently in the process of cleaning up an SQL database and we've come across a large amount of Stored Procedures which only have slight differences between them. We wish to consolidate them into a single proc to allow for easier maintenance.
Problem
Below are just two examples of the kind of stored procs we're attempting to merge (do note, these are simplified versions, not the actual procs).
Stored Procedure - Current Bookings
ALTER PROCEDURE [dbo].[SelectCurrentBookings]
#client_FK INT, #startDate DATETIME, #endDate DATETIME
AS
BEGIN
SELECT ROW_NUMBER() OVER (ORDER BY [Booking].[bookingDateTime]) [RowNumber],
[Booking].[booking_PK] [Booking ID],
[Booking].[bookingDateTime] [Booking Date],
[Booking].[bookingDuration] [Duration],
[Booking].[client] [Client Name],
CASE WHEN [Booking].[bookingStatusCode_FK] IN (4,8,9,7,16) THEN 1 ELSE 0 END [Unserviced],
FROM [Booking]
WHERE [client_FK] = #client_FK
AND [Booking].[bookingStatusCode_FK] IN (1,2,14,17)
AND [Booking].[bookingDateTime] >= #startDate
AND [Booking].[bookingDateTime] < DATEADD(d,1,#endDate)
AND [Booking].[deleted] = 0
END
Stored Procedure - Archived Bookings
ALTER PROCEDURE [dbo].[SelectArchivedBookings]
#client_FK INT, #startDate DATETIME, #endDate DATETIME
AS
BEGIN
SELECT ROW_NUMBER() OVER (ORDER BY [Booking].[bookingDateTime]) [RowNumber],
[Booking].[booking_PK] [Booking ID],
[Booking].[bookingDateTime] [Booking Date],
[Booking].[bookingDuration] [Duration],
[Booking].[client] [Client Name],
CASE WHEN [Booking].[bookingStatusCode_FK] IN (4,8,9,7,16) THEN 1 ELSE 0 END [Unserviced],
FROM [Booking]
WHERE [client_FK] = #client_FK
AND [Booking].[bookingStatusCode_FK] IN (1,2,14,4,9,7,16,13)
AND [Booking].[bookingDateTime] >= #startDate
AND [Booking].[bookingDateTime] < DATEADD(d,1,#endDate)
AND [Booking].[deleted] = 0
END
The code which invokes the stored procs is in VB.NET
Dim Command As DbCommand = _db.GetStoredProcCommand("SelectCurrentBookings")
_db.AddInParameter(Command, "client_FK", DbType.Int32, ClientID)
_db.AddInParameter(Command, "startDate", DbType.DateTime, StartDate)
_db.AddInParameter(Command, "endDate", DbType.DateTime, EndDate)
Return _db.ExecuteDataSet(Command)
As you can see, the only difference between the above stored procs are the values supplied to the WHERE IN.
Is there a way for us to modify this and have the list of values supplied through a parameter or variable?

Answer 1

If the objective is to reduce maintenance effort I would humbly suggest that moving data values out of the data layer and hard-coding them in the logic layer, perhaps in several places, is maybe not contributing to this objective.
Removing these explicit values from the queries will remove information the optimiser can use to create a plan. Be careful you replace it with something better else query performance may suffer. I would posit these SPs are separated precisely so unique plans exist for each, especially if the queries are much more complex than is shown. Compare the current plans against each other and whatever you end up with to ensure you haven't regressed.
One option may be to create a new "list" table:
ListName StatusCode
current 1
current 2
...
current 17
archive 1
archive 2
archive 4
...
archive 16
Join to this table instead of using an IN clause. Qualify the join by ListName, which is passed as a parameter. A unique clustered index on (ListName, StatusCode) would be good. You may consider creating a filtered statistic for each ListName. Create a foreign key constraint if you hold a master list of status values.
The stored procedure then becomes
ALTER PROCEDURE [dbo].[SelectCurrentBookings]
#client_FK INT, #startDate DATETIME, #endDate DATETIME,
#ListName char(10)
AS
BEGIN
SELECT ROW_NUMBER() OVER (ORDER BY [Booking].[bookingDateTime]) [RowNumber],
...
FROM [Booking]
INNER JOIN dbo.List as l
ON [Booking].[bookingStatusCode_FK] = l.StatusCode
AND l.ListName = #ListName
WHERE [client_FK] = #client_FK
AND [Booking].[bookingDateTime] >= #startDate
AND [Booking].[bookingDateTime] < DATEADD(d,1,#endDate)
AND [Booking].[deleted] = 0
END
The calling code gains a parameter
Dim Command As DbCommand = _db.GetStoredProcCommand("SelectCurrentBookings")
_db.AddInParameter(Command, "client_FK", DbType.Int32, ClientID)
_db.AddInParameter(Command, "startDate", DbType.DateTime, StartDate)
_db.AddInParameter(Command, "endDate", DbType.DateTime, EndDate)
_db.AddInParameter(Command, "ListName", DbType.String, "current") //correct type needed
Return _db.ExecuteDataSet(Command)
This way meanings for status codes are recorded in one place and good statistics are available to the optimiser. Whether this is faster than the current implementation, only testing can tell.

Answer 2

"We wish to consolidate them into a single proc to allow for easier maintenance."
I would agree, having multiple stored procedure's that do the same thing except a certain condition can be maintenance hell; especially if these are all over the place. Below I have a few different options and or solutions you could try out. With this in mind, I will let you decide how you would like to approach this as each option is different as in execution plans etc.
"the only difference between the above stored procs are the values supplied to the WHERE IN"
Option One
Create a system table for example: dbo.System_Booking_Status. This table would only need a few columns: System_Status_ID (Primary Key),Booking_Status_Code INT NOT NULL and Booking_Status BIT NOT NULL
Now you can populate this table with your values. The booking status column could mean 1 for current and 2 for archive; however you wish. Or make it a VarChar(15) type and use a description (Current or Archived) so it is distinguished OR a Char(1) type and use (C - for current & A - for archive).
Now that you have a system table you can join to we need to tell the stored procedure to do so and when. I used a new parameter called: status which would need to be passed in when you make the call to either get the current and or archived records back.
ALTER PROCEDURE [dbo].[SelectCurrentBookings]
#client_FK INT, #startDate DATETIME, #endDate DATETIME, #status INT
AS
BEGIN
IF #status = 1 --current
BEGIN
SELECT ROW_NUMBER() OVER (ORDER BY b.[bookingDateTime]) [RowNumber],
b.[booking_PK] [Booking ID],
b.[bookingDateTime] [Booking Date],
b.[bookingDuration] [Duration],
b.[client] [Client Name],
CASE WHEN b.[bookingStatusCode_FK] IN (4,8,9,7,16) THEN 1 ELSE 0 END [Unserviced],
FROM [Booking] b
INNER JOIN dbo.System_Booking_Status sbs
ON sbs.Booking_Status_Code = b.bookingStatusCode_FK
AND sbs.Booking_Status = 1 --current?
WHERE [client_FK] = #client_FK
AND b.[bookingDateTime] >= #startDate
AND b.[bookingDateTime] < DATEADD(d,1,#endDate)
AND b.[deleted] = 0
END
ELSE
BEGIN
SELECT ROW_NUMBER() OVER (ORDER BY b.[bookingDateTime]) [RowNumber],
b.[booking_PK] [Booking ID],
b.[bookingDateTime] [Booking Date],
b.[bookingDuration] [Duration],
b.[client] [Client Name],
CASE WHEN b.[bookingStatusCode_FK] IN (4,8,9,7,16) THEN 1 ELSE 0 END [Unserviced],
FROM [Booking] b
INNER JOIN dbo.System_Booking_Status sbs
ON sbs.Booking_Status_Code = b.bookingStatusCode_FK
AND sbs.Booking_Status = 2 --archived?
WHERE [client_FK] = #client_FK
AND b.[bookingDateTime] >= #startDate
AND b.[bookingDateTime] < DATEADD(d,1,#endDate)
AND b.[deleted] = 0
END
END
Now you do not have to use hard coded values and eliminate the IN clause by using the INNER JOIN.
Option Two (Quick n Dirty)
Pass in another variable to either determine if you want current or archived records back.
IF #status = 1....
BEGIN
--Normal query executed for active...
END
ELSE
BEGIN
--Normal query executed for archived...
END
Option Three
You can pass in XML of the values that you would need. Parse this XML out into a Table Variable and then join to this. It would eliminate your IN clause and better execution plan as well.
For example:
Declare #Status_Codes XML = ''
DECLARE #StatusTable TABLE
(
Status_Code INT
)
-- Parse the XML in to the temp table declared above
INSERT INTO #StatusTable(Status_Code)
SELECT
xmlData.A.value('.', 'INT')
FROM #Status_Codes.nodes('BookingStatus/StatusCode/Code') xmlData(A)
Now you have a Table Variable you can join to...
FROM [Booking] b
INNER JOIN #StatusTable s
ON s.Status_Code = b.bookingStatusCode_FK
Next you have to pass this data in from your function call. You can create a function that would return the formatted XML and pass that into your stored procedure call.
Public Shared Function ConstructXMLStatusCodes(ByVal intStatus As Integer) As String
Dim strBuilder As New System.Text.StringBuilder
If intStatus = 1 'active...
With strBuilder
.AppendLine("<BookingStatus>")
.AppendLine("<StatusCode>")
.AppendLine("<Code>1</Code>")
.AppendLine("<Code>2</Code>")
'continue to add more codes...
.AppendLine("</StatusCode>")
.AppendLine("</BookingStatus>")
End With
Else
'Create your builder with the archive...
End If
Return strBuilder.ToString()
End Function
Then make your call before passing it to your function OR make the call in your function; you have more than a few choices...
On another Note
I notice you are executing a DataSet but you are never returning one, I would use the DataTable.Load method that executes a reader and fills a table...
Good Luck!