title: MySQL add column if not exist
body: <pre><code>IF NOT EXISTS (SELECT * FROM INFORMATION_SCHEMA.COLUMNS
    WHERE TABLE_NAME = 'email_subscription' AND COLUMN_NAME = 'subscribe_all')
    THEN 
    ALTER TABLE email_subscription
    ADD COLUMN subscribe_all TINYINT(1) DEFAULT 1,
    ADD COLUMN subscribe_category varchar(512) DEFAULT NULL;
  </code></pre>
  
  <p>I had a look at huge amount of examples. but this query doesn't work, I got error of:</p>
  
  <blockquote>
    <p>ERROR 1064 (42000): You have an error in your SQL syntax; check the
    manual that corresponds to your MySQL server version for the right
    syntax to use near 'IF NOT EXISTS (SELECT * FROM
    INFORMATION_SCHEMA.COLUMNS   WHERE TABLE_NAME =' at line 1</p>
  </blockquote>