How to use CASE with UPDATE?

Question

Hi all. I'm trying to update multiple rows in a MS-Access
database using a single query, with different values for each row.
Here's a simplified example of the code:
<cfquery name="JustInCase" datasource="variables.DB">
Update Users
SET First_Name =
CASE WHEN ID = 1 THEN 'Nini' END,
SET Last_Name
CASE WHEN ID = 32 THEN 'Yumpi' END
</cfquery>
Trying to run something like this produces the following
error message:
[Macromedia][SequeLink JDBC Driver][ODBC
Socket][Microsoft][ODBC Microsoft Access Driver] Syntax error
(missing operator) in query expression 'CASE WHEN ID = 1 THEN
'Nini' END'.
I realize this can easily be done using multiple queries, but
the actual code will contain many updates, and I would like to at
least test the possibility of improving performance using a single
query instead of multiple queries. I would greatly appreciate any
help with this - I've been trying all kinds of variations, and
nothing seems to satisfy emperor ColdFusion. Any ideas?

Answer 1

Case might be a verity tag but it is also a valid sql keyword
in many dbs. I use it in select clauses frequently and have seen it
used in where clauses.
The problem with the original query is that, it the value of
id is not 1, this part
SET First_Name =
CASE WHEN ID = 1 THEN 'Nini' END,
will cause a syntax error. For those values of 1 and 32, this
syntax will run, but will update every row in the table which might
not be the plan.
update users
set
case when id = 1 then first_name = 'Nini'
when id = 32 then last_name = 'Yumpi'
else first_name = first_name
end
ranger, your code will also fail if the value is neither 1
nor 32. You need a default case.