SET @story_share_table_exists = (
  SELECT COUNT(*)
  FROM information_schema.TABLES
  WHERE TABLE_SCHEMA = DATABASE()
    AND TABLE_NAME = 'story_share'
);

SET @story_share_template_exists = (
  SELECT COUNT(*)
  FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = DATABASE()
    AND TABLE_NAME = 'story_share'
    AND COLUMN_NAME = 'template_style'
);

SET @story_share_template_stmt = IF(
  @story_share_table_exists = 1 AND @story_share_template_exists = 0,
  "ALTER TABLE story_share ADD COLUMN template_style varchar(32) DEFAULT 'editorial' COMMENT 'Public template style' AFTER share_quote",
  'SELECT 1'
);

PREPARE story_share_template_stmt FROM @story_share_template_stmt;
EXECUTE story_share_template_stmt;
DEALLOCATE PREPARE story_share_template_stmt;