Stored Procedure WHERE LIKE ID or NAME - sql

Question

Group,
I am trying to create a stored procedure using one variable #Customer. What I want to do is put something in my WHERE clause that says if it is a number search the CustomerID field where the number entered is LIKE CustomerID... If a char is entered search the CustomerName field where the text entered is LIKE CustomerName. Below is an example of what I am trying to do:
CREATE PROCEDURE [dbo].[uspGetCustomer] (#Customer VARCHAR(100))
AS
SET NOCOUNT ON
SELECT *
FROM dbo.Customers
WHERE CASE WHEN ISNUMERIC(#Customer) THEN CustomerID LIKE #Customer + '%'
ELSE CustomerName LIKE #Customer + '%' END
Any suggestions?

Answer 1

I'd do it using an IF statement, since putting that logic in the WHERE makes it kind of hard to read later on:
DECLARE #match = #CustomerID + '%'
IF ISNUMERIC(#CustomerID) = 1
BEGIN
SELECT * FROM CUSTOMERS WHERE CustomerID LIKE #match
END ELSE BEGIN
SELECT * FROM CUSTOMERS WHERE CustomerNAME LIKE #match
END
update:
I'm wondering if the CustomerID field is an INT. If so then I'd change the query like so (and get rid of the #match variable):
... WHERE CustomerID = Cast(#CustomerID as INT) --if numeric
... WHERE CustomerNAME = #CustomerID + '%' --if not numeric
However, if it's some weird VARCHAR field that starts with a number and ends with other data, like '11_blah', then the LIKE plus wildcard works fine

Answer 2

Doing a single SQL statement that tries to solve both conditions will result in worst execution plan. Remeber that SQL has to generate one single plan to satisfy any value of the #variable. In your case when #customerID is numeric the proper plan would be to use an index on CustomerID. But when #customerID is a name the proper access would be an index on CustomerName. Given this dillema the optimizer will likely pick a plan that does a full scan, ie. not optimized in neither case.
The proper thing to do is to determine in your application if is an ID or a name and call two separate stored procedures, uspGetCustomerByID and uspGetCustomerByName, according to the value entered. If you must do this via one 'magic' API entry point (the all-powerful uspGetCustomer), then you already got seveal good answers.

Answer 3

It could just be me, but using a single variable to represent two different fields gives me the bad-practice willies. I would rewrite this stored procedure to take in two different, nullable variables (one int, CustomerID, and one varchar, CustomerName). It would look like this:
CREATE PROCEDURE [dbo].[uspGetCustomer] (
#CustomerID int = null,
#CustomerName VARCHAR(100) = null)
AS
IF #CustomerID IS NOT NULL BEGIN
SELECT * FROM Customers WHERE CustomerID = #CustomerID
END ELSE IF #CustomerName IS NOT NULL BEGIN
SELECT * FROM Customers WHERE CustomerName LIKE #CustomerName
END ELSE
--error handling, return empty set maybe?
END
If this simply isn't an option, then you could still use:
CREATE PROCEDURE [dbo].[uspGetCustomer] (#Customer VARCHAR(100))
AS
DECLARE #NameMatch;
IF ISNUMERIC(#Customer) = 1 BEGIN
SELECT * FROM Customers WHERE CustomerID = CAST (#Customer AS int)
END ELSE BEGIN
SET #NameMatch = '%' + #Customer + '%'
SELECT * FROM Customers WHERE CustomerName LIKE #NameMatch
END

Answer 4

Use:
CREATE PROCEDURE [dbo].[uspGetCustomer] (#Customer VARCHAR(100))
AS
BEGIN
IF ISNUMERIC(#Customer) = 1
BEGIN
SELECT *
FROM dbo.CUSTOMERS
WHERE customerid LIKE #Customer + '%'
END
ELSE
BEGIN
SELECT *
FROM dbo.CUSTOMERS
WHERE customername LIKE #Customer + '%'
END
END

Answer 5

Do something like this:
CREATE PROCEDURE [dbo].[uspGetCustomer] (
#CustomerID INT = NULL
#Customer VARCHAR(100) = NULL
)
AS
SET NOCOUNT ON
IF #CustomerID is not null
BEGIN
SELECT * FROM dbo.Customers
WHERE CustomerID = #CustomerID
END
ELSE
BEGIN
SELECT * FROM dbo.Customers
WHERE CustomerName LIKE #CustomerID + '%'
END
SET NOCOUNT OFF

Answer 6

I'd keep it simple and assume that customer names are never numeric:
SELECT *
FROM dbo.Customers
WHERE CustomerID LIKE #Customer + '%'
OR CustomerName LIKE #Customer + '%'
Alternatively, if you really don't want to match a numeric customer against its name, you can check like:
WHERE (IsNumeric(#Customer) = 1 AND CustomerID LIKE #Customer + '%')
OR (IsNumeric(#Customer) = 0 AND CustomerName LIKE #Customer + '%')
But then, how would you search for a customer with a numeric name? And by the way... a search like this will find customer 121 if you search for 12.

Answer 7

SELECT *
FROM dbo.Customers
WHERE ISNUMERIC(#Customer) = 1
AND CustomerID = CAST(#Customer AS INTEGER)
UNION ALL
SELECT *
FROM dbo.Customers
WHERE NOT ISNUMERIC(#Customer) = 1
AND CustomerName LIKE #Customer + '%'
This will use the approproate indexes on CustomerID and CustomerName

Answer 8

Oh just do it this way....
IF ISNUMERIC(#Customer) THEN
SELECT * FROM .... CustomerID = #Customer
ELSE
SELECT * FROM ... CustomerName LIKE #Customer
But you would want it more maintainable I suppose...
declare #basequery NVARCHAR(4000)
declare #params NVARCHAR(4000)
set #base_query = 'select * from dbo.Customers where '
IF ISNUMERIC(#Customer) THEN
SET #base_query = #base_query + 'customerid = #xCustomer'
SET #params = '#xCustomer int'
END
ELSE
SET #base_query = #base_query + 'customerName LIKE #xCustomer + ''%'' '
SET #params = '#xCustomer nvarchar(1000)'
END
exec sp_execuresql #base_query, #params, #Customer
Of course I would only recommend this kind of dynamic sql for more complex kinds of filtering.

Answer 9

I believe this will do it:
WHERE CustomerID LIKE
CASE WHEN IsNumeric(#Customer) = 1 THEN
CustomerID
ELSE
CustomerName + '%'
END

Answer 10

Keep it simple, have an index on each, determine on the front-end which one it is and set the correct parameter.
CREATE PROCEDURE dbo.getCustomer
(#CustomerID int = null,
#CustomerName VARCHAR(100) = null)
AS
SET NOCOUNT ON
SELECT *
FROM Customers
WHERE CustomerID = #CustomerID
or CustomerName like #CustomerName + '%'