CODEWITHSUNDEEP
mysqlsqlinsert
Matt
Matt

Reputation: 3894

SQL - How to make a conditional INSERT

Using only MySQL, I'm seeing if it's possible run an insert statement ONLY if the table is new. I successfully created a user variable to see if the table exists. The problem is that you can't use "WHERE" along with an insert statement. Any ideas on how to get this working?

// See if the "country" table exists -- saving the result to a variable
SELECT
    @table_exists := COUNT(*)
FROM
    information_schema.TABLES
WHERE
    TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'country';

// Create the table if it doesn't exist
CREATE TABLE IF NOT EXISTS country (
    id INT unsigned auto_increment primary key,
    name VARCHAR(64)
);

// Insert data into the table if @table_exists > 0
INSERT INTO country (name) VALUES ('Afghanistan'),('Aland Islands') WHERE 0 < @table_exists;

Upvotes: 5

Views: 5468

Answers (2)

mmattax
mmattax

Reputation: 27670

Use an if statement instead of the where clause:

http://dev.mysql.com/doc/refman/5.0/en/if-statement.html

Upvotes: 2

FlySwat
FlySwat

Reputation: 175583

IF @TableExists > 0 THEN
   BEGIN
       INSERT INTO country (name) VALUES ('Afghanistan'),('Aland Islands');
   END

Upvotes: 6

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