CODEWITHSUNDEEP
javamysql
AL̲̳I
AL̲̳I

Reputation: 2461

Insert into `table` where not exist

I want to insert values into a table but need to check if the value exist in the last row or not. I normally insert values like

INSERT INTO `table` (`column1`,`column2`,`column3`,`column4`) VALUES ('value1','value2','value3','value4')

But now I need to put a check, if the value1 exist in the last row of the table do not insert, insert otherwise.

For that I am trying to use 

WHERE NOT EXISTS

I actually want to check the last row of the table if the value exist then it should not duplicate it.

Upvotes: 0

Views: 1268

Answers (4)

0xCAFEBABE
0xCAFEBABE

Reputation: 5666

You can state explicitly what happens when the primary key for a table already exists. Example:

INSERT INTO table (...) VALUES (...) ON DUPLICATE KEY UPDATE

Upvotes: 1

Idaho
Idaho

Reputation: 1393

Adding an unique constraint on the pair (column 1, column 2) isn't a better way to do that ?

Upvotes: 0

Yevgeny Simkin
Yevgeny Simkin

Reputation: 28379

as an aside, as per the documentation, in the WHERE NOT EXISTS select, you don't need to specify fields (value1, value2, in your case) because that is entirely ignored. So just use *

In any event, I believe this will answer your question: How to 'insert if not exists' in MySQL?

Upvotes: 0

Jeff Watkins
Jeff Watkins

Reputation: 6359

Alias the sub select. It is mandatory in MySQL.

Upvotes: 0

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