Syntax for multiple cases in MySQL - mysql

Question

I have a MySQL update statement which is attempting to reset two columns: label and PersTrCode. (This is in a Coldfusion program.) I'm doing this with CASE statements but I can't seem to get the syntax right -- I keep getting an error. The code:
<cfquery name = 'nonull' datasource = "Moxart">
update FinAggDb
set Label = CASE
WHEN PersActIncOutg = 'I' && PersTrCode IS NULL THEN 'Total Income'
WHEN PersActIncOutg = 'O' && PersTrCode IS NULL THEN 'Total Expense'
WHEN PersActIncOutg IS NULL && PersTrCode IS NULL THEN ' '
ELSE PersTrCode
END
SET PersTrCode = CASE
WHEN PersTrCode IS NULL THEN 'Total'
ELSE PersTrCode
END
</cfquery>
The error is the usual informative statement:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SET PersTrCode = CASE WHEN PersTrCode IS NULL THEN 'Total' ELSE PersTrCode ' at line 8
Are multiple CASE statements not allowed? Or can someone tell me how to fix this?

Answer 1

An update statement has only one set clause, with the various columns you want to update separated by commas. Also, note that it's more common to use and and not &&, although both are valid in MySQL:
update FinAggDb
set Label = CASE
WHEN PersActIncOutg = 'I' AND PersTrCode IS NULL THEN 'Total Income'
WHEN PersActIncOutg = 'O' AND PersTrCode IS NULL THEN 'Total Expense'
WHEN PersActIncOutg IS NULL AND PersTrCode IS NULL THEN ' '
ELSE PersTrCode
END
, -- comma here, not a second "set" clause
PersTrCode = CASE
WHEN PersTrCode IS NULL THEN 'Total'
ELSE PersTrCode
END