How to insert a row only if there is none?

Question

MySQL

Let's say we have a table:

col1 | col2 | col 3
--------------------
v031 | v034 | v999
v031 | v385 | v555

It is necessary to avoid adding another line "v031", "v034", "v999'. That is, if the values ​​in all three columns completely match, the line should not be inserted.

Answer 1

You can use the not exists construct in an insert query
https://dev.mysql.com/doc/refman/5.7/en/exists-and...

Answer 2

UNIQUE index on these three columns + INSERT IGNORED