When you think ASP, think...
Recent Articles
All Articles
ASP.NET Articles
ASPFAQs.com
Message Board
Related Web Technologies
User Tips!
Coding Tips

Sections:
Sample Chapters
Commonly Asked Message Board Questions
JavaScript Tutorials
MSDN Communities Hub
Official Docs
Security
Stump the SQL Guru!
XML Info
Information:
Feedback
Author an Article
ASP ASP.NET ASP FAQs Message Board Feedback

The 4 Guys Present: ASPFAQs.com

Jump to a FAQ
Enter FAQ #:
..or see our 10 Most Viewed FAQs.

4GuysFromRolla.com : ASP FAQS : Databases, Queries


Question:

How do I use CASE in Transact SQL?


[Print this FAQ]

Answer: Case Statements in Transact SQL
Selection criteria in your Stored Procedures will need to change at times if you really want high reuse out of your Stored Procs. You can use CASE to do this. CASE is very similar to SELECT CASE in any othr data processing language.

The following stored procedure will select a different Price from the database based on the login level of the user.

CREATE PROCEDURE SP_Products
@cat int,
@Price nvarchar(10)
 AS

Select CODE,TITLE,Version,Status,
Case @Price
    When 'Price' THEN Price
    When 'PriceA' Then PriceA
    When 'PriceB' Then PriceB
    When 'PriceC' Then PriceC
End
,Lots,LotsOf,Description,Pic
From Products
Where Category = @cat ORDER BY CODE

Based on what you have just seen you may be thinking CASE will work everywhere. It would be only practical to assume this will work with the ORDER BY clause.

CREATE PROCEDURE SP_Products
@cat int,
@Price nvarchar(10)
 AS

Select CODE,TITLE,Version,Status,Lots,LotsOf,Description,Pic
From Products Where Category = @cat ORDER BY

Case @Price
    When 'Price' THEN Title
    When 'PriceA' Then Version
    When 'PriceB' Then Status
    When 'PriceC' Then Lots
End

Well guess what? It will compile file. The syntax checker in SQL Server will not throw an error but IT DOES NOT WORK. SQL server is very fussy about where CASE is used. And in most cases unlogically.

UPDATE (Feb. 6th, 2002)
The above comments are in regard to Microsoft SQL Server 6.5. The above code works in Microsoft SQL Server 7.0 and Microsoft SQL Server 2000.



Visit SQLteam.com for more great information on Transact SQL!


FAQ posted by Rob Taylor at 12/9/2000 4:18:33 AM to the Databases, Queries category. This FAQ has been viewed 75,026 times.

Do you have a FAQ you'd like to suggest? Suggestions? Comments? If so, send it in! Also, if you'd like to be a FAQ Admin (creating/editing FAQs), let me know! If you are looking for other FAQs, be sure to check out the 4Guys FAQ and Commonly Asked Messageboard Questions!

Most Viewed FAQs:

1.) How can I format numbers and date/times using ASP.NET? For example, I want to format a number as a currency. (761643 views)
2.) I am using Access and getting a 80004005 error (or a [Microsoft][ODBC Microsoft Access Driver] The Microsoft Jet database engine cannot open the file '(unknown)' error) when trying to open a connection! How can I fix this problem? (207777 views)
3.) How can I convert a Recordset into an array? Also, how can I convert an array into a Recordset? (202549 views)
4.) How can I quickly sort a VBScript array? (196039 views)
5.) How can I find out if a record already exists in a database? If it doesn't, I want to add it. (156019 views)
6.) How do I display data on a web page using arrays instead of Do...While...MoveNext...???... (152331 views)
7.) When I get a list of all files in a directory via the FileSystemObject, they aren't ordered in any reasonable way. How can I sort the files by name? Or by size? Or by date created? Or... (140381 views)
8.) For session variables to work, must the Web visitor have cookies enabled? (110162 views)
9.) Can I send emails without using CDONTS? (107083 views)
10.) How can I take the result of a SELECT...MULTIPLE or a group of same-named checkboxes and turn it into a query? That is, if the user selects 3 answers, how can I construct a query that looks for all 3? (106308 views)
Last computed at 9/17/2007 3:22:00 AM


ASP.NET [1.x] [2.0] | ASPMessageboard.com | ASPFAQs.com | Advertise | Feedback | Author an Article