SQL Syntax for checking duplicates prior to update (not DUPLICATE KEY UPDATE) - mysql

Question

I have a syntactical question with attempting an UPDATE if 2 non key fields are matched. -- INSERT if not matched.
Let me start by saying I have a working query that involves a SELECT with an ON DUPLICATE KEY UPDATE. Now I am just curious, can it be done differently?
Out of sheer curiosity, I am trying this in a manner that will not require the primary key. This really is just an experiment to see if it can be done.
What I want is like ON DUPLICATE KEY UPDATE -- However:
let's pretend I don't know the key , and
let's pretend I can't get the key with a SELECT
Here is the data structure I have:
+--------------------------------------------------------------------------+
| id | contractor_id | email_type_id | email_address |
+--------------------------------------------------------------------------+
Table creation:
CREATE TABLE `email_list` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`contractor_id` int(11) NOT NULL,
`email_type_id` int(11) NOT NULL,
`email_address` varchar(45) COLLATE utf8_unicode_ci NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `id_UNIQUE` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=13 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
Now what I am trying to do without a select and without ON DUPLICATE KEY UPDATE is -- If contractor_id and email_type_id are matched -- UPDATE the email_address -- else INSERT.
If have tried this -- (I know I am breaking my own rule of no SELECT):
IF EXISTS (SELECT * FROM email_list WHERE contractor_id = 1166)
UPDATE email_list SET (email_address='herky_jerky#snailmail.com')
WHERE contractor_id = 1166 AND email_type_id = 4
ELSE
INSERT INTO email_list VALUES (
contractor_id = 1166,
email_type_id = 4,
email_address = 'herky_jerky#snailmail.com');
I understand why this doesn't work .. I just don't know what the fix for it is -- It feels a little clunky too using an IF - ELSE statement. Also I don't want to use a SELECT -- So then I thought about using just an IF like:
UPDATE email_list SET email_address = 'herky#jerky.com'
WHERE contractor_id = 1166 AND email_type_id = 4
IF ##ROWCOUNT=0
INSERT INTO email_list VALUES (
contractor_id = 1166,
email_type_id = 4,
email_address = 'herky#jerky.com');
But I don't understand why that one doesn't work. This is just an exercise to see how creative one can be with this type of query. I think both of my ideas are doable -- Can anyone find a fix for either query to make it work?
I'd also love to see other, more creative, ways of attempting what I am asking as well!

Answer 1

I'd implement this using an UPDATE followed by a test of ROW_COUNT() and if no rows were updated, then INSERT.
drop table if exists t;
create table t (id int, x int, y int, str varchar(255));
insert into t (id, x, y, str) values (1, 2, 3, 'foo');
select * from t;
update t set str = 'bar'
where x = 2 and y = 3;
insert into t (id, x, y, str)
select 1, 2, 3, 'inserted'
from dual
where row_count() = 0;
select * from t;
update t set str = 'baz'
where x = 20 and y = 30;
insert into t (id, x, y, str)
select 10, 20, 30, 'baz'
from dual
where row_count() = 0;
select * from t;
drop table t;
You can see it in action here: https://rextester.com/FRFTE79537
The idea here is you do the UPDATE first, followed by an INSERT ... SELECT where the SELECT only returns a row if ROW_COUNT() = 0 is true, and that's only true if the UPDATE didn't match any rows.