PHP - Skip if already exists

Question

I have been comparing 2 tables using JOIN and storing my result in another table called macadd. Each time I run my code its generating duplicate record in table macadd. How I can stop same record being stored again and again. Here is code which is generating duplicates:

$query = mysqli_query($conn, "insert into macadd (mac)
select volley.mac from volley
inner join savedemail on savedemail.email = volley.email");

As This query is comparing the rows. I am completely out of logic here that how can I make a variable out of this sql query. So that using that I can check weather record exist or not

Do you want insert if not exists? http://stackoverflow.com/questions/3164505/mysql-insert-record-if-not-exists-in-table — Kelvin, Feb 18 '16 at 15:21
i am not able to use `(mysqli_num_rows($query) > 0)` here because there is no variable through which I can validate it, — , Feb 18 '16 at 15:24
you need slice your query to 2 other query. The first you check exists, and if not exist you run the second query : `insert` — Kelvin, Feb 18 '16 at 15:28

Jim Wright · Answer 1 · 2016-02-18T16:59:51.670

0

You want to use INSERT IGNORE.

$query = mysqli_query($conn, "insert ignore into macadd (mac)
select volley.mac from volley
inner join savedemail on savedemail.email = volley.email");

edited Feb 18 '16 at 16:59

answered Feb 18 '16 at 15:27

Jim Wright

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Does MySql have such expression? I know of "ON DUPLICATE KEY UPDATE" or "INSERT ..WHERE NOT EXISTS(....)", never heard of that – Damien Pirsy Feb 18 '16 at 15:33
@jim its not working even not inserting records – Feb 18 '16 at 15:47
@shreyash-singh Sorry I meant INSERT IGNORE. I have updated my answer. – Jim Wright Feb 18 '16 at 16:52

PHP - Skip if already exists

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