SELECT 
  q_product_descriptions.product_id, 
  q_product_descriptions.short_description, 
  IF(
    q_product_descriptions.short_description = '', 
    q_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  q_product_descriptions 
WHERE 
  q_product_descriptions.product_id IN (13647, 16011, 16410, 16628) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00119

JSON explain

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      "query_cost": "9.61"
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    "table": {
      "table_name": "q_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 4,
      "rows_produced_per_join": 4,
      "filtered": "100.00",
      "index_condition": "((`portal`.`q_product_descriptions`.`product_id` in (13647,16011,16410,16628)) and (`portal`.`q_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "8.81",
        "eval_cost": "0.80",
        "prefix_cost": "9.61",
        "data_read_per_join": "15K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ]
    }
  }
}

Result

product_id short_description full_description
13647 <ul class="a-unordered-list a-vertical a-spacing-none"><li><span class="a-list-item">Extended nine-foot cable that plugs into your console</span></li><li><span class="a-list-item">Adjustable vibration feedback for a personalized gaming experience</span></li><li><span class="a-list-item">Compact ergonomics for comfortable play</span></li><li><span class="a-list-item">Works with most Windows Vista-based PCs and Integrated headset port for Xbox LIVE play</span></li><li><span class="a-list-item">PLEASE NOTE: This item is discontinued in the U.S. and is sourced from another country, therefore, the product packaging may have some other languages written on it besides English. Otherwise, the unit itself is the same as U.S. version.</span></li></ul>
16011 <ul class="a-unordered-list a-vertical a-spacing-none"><li><span class="a-list-item">Get revenge with the very latest experimental weaponry -- and the military experience of your fallen comrades, encoded in special bio-chips</span></li> <li><span class="a-list-item">Dynamically use the environment to your advantage -- conform to objects and terrain, and fire from protected positions</span></li> <li><span class="a-list-item">Use the Rogue's enhanced phsyical abilities to to gain the advantage over your enemy -- run, leap, and dive for cover</span></li> <li><span class="a-list-item">Create any type of ammunition you want, when you want it</span></li> <li><span class="a-list-item">Upgrade your bio-chipped equipment to gain strategic advantage over your foes</span></li> <li><span class="a-list-item">Get revenge with the very latest experimental weaponry -- and the military experience of your fallen comrades, encoded in special bio-chips</span></li> </ul>
16410 <ul class="a-unordered-list a-vertical a-spacing-none"><li><span class="a-list-item">Millions of challenging games, Three different levels of difficulty</span></li> <li><span class="a-list-item">Play with or without answer prompts, Backlit screen for lowlight play</span></li> <li><span class="a-list-item">Sound effects indicate startup, game start and stop, correct and incorrect answers, etc.</span></li> <li><span class="a-list-item">Displays time and date, Alarm clock function</span></li> <li><span class="a-list-item">Requires two AAA batteries included, Model TY-500B</span></li> </ul>
16628 <ul class="a-unordered-list a-vertical a-spacing-none"><li><span class="a-list-item">This blackbox car recorder can be windshield mount with full hd 1080p cmd full shading. Video is striking for quality, give high assurance. Pyle PLCMDVR72 camera recorders is an absolute necessity to have frill for your vehicle.</span></li> <li><span class="a-list-item">170 degrees road view auto camcorder, worked in IR with external lights, striking night video quality. A more sharp picture on your auto camera recorder 1080p HD your onlooker never obstructed. Have security while out & about</span></li> <li><span class="a-list-item"> Records sharper image subsequently when engine starts. Safety discovery g-sensor and manual crisis bolt catch. Current video 7 inch dash cam from overwritten, Accident free driving park protect canine for perception of your vehicle</span></li> <li><span class="a-list-item">Loop digital car camera dvr pip view record engages to overwrite video in vehicle with the freshest, Modified and reliable sound recording. Micro sd card up to 32GB. </span></li> </ul>