MySQL如何在WHERE中使用两个加密字段更新记录

Question

Not certain this is possible, but I'd like to do this in one step if I can. I'd like to update field 3, if my passed-in values match two other fields that are encrypted. Here is what I have that isn't working...

UPDATE tbl 
SET field3=CONCAT(field3, 'some additional value') 
WHERE field1 = ENCRYPTION_APPROACH('my_value_in_the_clear', ENCRYPTION_SETTINGS) AND 
field2 = ENCRYPTION_APPROACH('my_other_value_in_the_clear', ENCRYPTION_SETTINGS);

Fields 1 and 2 are NOT keys, but they are programmatically guaranteed to be unique. The encryption appears to be working, I can use the same approach to initially INSERT the record, and then later SELECT it. However, when I run this with verified test data, I get "0 rows affected", and no error messages.

I can just do a compound call where I first select the record with this same approach, and then update it by it's key (which is working for a different call). But I'd really like to keep this to one step if I can. Thoughts?

Answer 1

Aha!

After some looking around, I found the REAL solution. Any time you have a CONCAT and some records are failing, using this little trick...

UPDATE tbl 
SET field3=IFNULL(CONCAT(field3, 'some additional value'), 'some additional value')
WHERE field1 = ENCRYPTION_APPROACH('my_value_in_the_clear', ENCRYPTION_SETTINGS) AND 
field2 = ENCRYPTION_APPROACH('my_other_value_in_the_clear', ENCRYPTION_SETTINGS);

It wasn't the encryption that was failing... it was when CONCAT was acting on a null field for the first time, it was returning a null. This little trick gets you past the first time you attempt to concat the previous value and works on all subsequent calls!