how to use if exist else in mysql statement

Question

i'm trying to write a if exists else sql which will further use in c# winform with mysql, here is the test

IF NOT EXISTS(SELECT 1 from products where entity_id=1) select * from products;

i ran above sql in adminer but there is a error message, Syntax error near 'select * from products' at line 1

Anyone know what is the problem?

http://stackoverflow.com/questions/15383852/sql-if-exists-update-else-insert-into — Ofir Winegarten, Feb 15 '17 at 19:04

Danilo Bustos · Answer 1 · 2017-02-15T19:32:53.877

0

try this:

  DELIMITER $$

        DROP PROCEDURE IF EXISTS `verifyExist` $$
            CREATE PROCEDURE `verifyExist`()
            BEGIN
           IF NOT EXISTS(SELECT 1 from products where entity_id=1) THEN 
            select * from products;
          END IF;
    END$$

        DELIMITER ;

edited Feb 15 '17 at 19:32

answered Feb 15 '17 at 19:23

Danilo Bustos

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This is the syntax for mssql not mysql – Ofir Winegarten Feb 15 '17 at 19:26
Edit my answer with the create procedure. – Danilo Bustos Feb 15 '17 at 19:37

score 0 · Accepted Answer · answered Feb 15 '17 at 19:23

First of all you should create a UNIQUE constraint on the columns.

ALTER TABLE products  ADD CONSTRAINT fk_products UNIQUE (column1, column2, etc..)

Then just insert the data:

INSERT INTO products (column1, column2, etc..) VALUES(value1, value2, etc..) ON DUPLICATE KEY UPDATE column1 = newValue, column2 = newValue2;

how to use if exist else in mysql statement

2 Answers2