Update if row > 0 OR INSERT on Mysql - mysql

Question

How to I can create a query for update, if select result is bigger then 0, else execute insert?
I had try execute this code, but is not work
select
case
where count(id) > 0 (update product set description = 'blablabla' where id_fk1 = 3 AND id_fk2 = 4)
else (insert into product (description) values('blablabla')
end
I know this is a select code, it will not work, but I don't know how to use If in mysql

Answer 1

you can use this example foreign-keys
there is a way to compose single query which compose single query with 'update ...' and 'insert into...'
or, if i misunderstood you, you can use this one insert-on-duplucate

Answer 2

What you need is INSERT with ON DUPLICATE KEY UPDATE clause:
https://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html

Answer 3

This has been asked before:
Insert into a MySQL table or update if exists
Contains many interesting answers.

Answer 4

Presumably, you want to insert the paid id = 3, description = 'blablabla' into the table. If it exists, then update the description.
You can use insert . . . on duplicate key insert, assuming that id is declared as the primary key or as a unique key. You would do this as:
create unique key product_id on product(id);
Then the following statement does what you want:
insert into product(id, description)
select 3, 'blablabla'
on duplicate key insert description = values(description);
EDIT:
I think the same idea applies to two foreign keys:
create unique key product_fk1_fk2 on product(id_fk1, id_fk2);
insert into product(id_fk1, id_fk2, description)
select 3, 4, 'blablabla'
on duplicate key insert description = values(description);

Answer 5

It will be base on the number of your query result, right?
$result=mysqli_query($con,"SELECT * FROM product");
if(mysqli_num_rows($result)==0){
mysqli_query($con,"INSERT INTO product (description) VALUES ('blah')");
}
else {
mysqli_query($con,"UPDATE product SET description='blah'");
}
If you're trying to base it on your id field, try this:
$result=mysqli_query($con,"SELECT * FROM product");
if(mysqli_num_rows($result)==0){
mysqli_query($con,"INSERT INTO product (description) VALUES ('blah')");
}
else
while($row=mysqli_fetch_array($result)){
$id=$row['id'];
if($id>0){
mysqli_query($con,"UPDATE product SET description='blah' WHERE id='$id'");
}
} /* END OF WHILE LOOP */
} /* END OF ELSE */