SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (205) 
  AND cscart_product_descriptions.lang_code = 'ja'

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "const",
      "possible_keys": ["PRIMARY", "product_id"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "ref": ["const", "const"],
      "rows": 1,
      "filtered": 100
    }
  }
}

Result

product_id short_description full_description
205 <p> 最高300MbpsでHDビデオストリーミングやオンラインゲームを快適にご利用いただける高機能ルーターです。<br /> 4基のギガビットイーサネットポート、プリンタ用USBポートに加え、SDカードスロットも搭載。DLNA対応で多様な機器と接続できます。</p> <h3 style="margin-top: 10px; margin-right: 0px; margin-bottom: 6px; margin-left: 0px; font-size: 14px; font-weight: 400; vertical-align: baseline; border-image: initial; outline-width: 0px; outline-style: initial; outline-color: initial; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; line-height: 14px; font-family: myriad-pro-1, myriad-pro-2; visibility: visible; color: #e22736; padding: 0px; border: 0px initial initial;"> 特徴:</h3> <ul style="margin-top: 0px; margin-bottom: 20px; margin-left: 0px; vertical-align: baseline; border-image: initial; outline-width: 0px; outline-style: initial; outline-color: initial; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; list-style-position: initial; list-style-image: initial; color: #555555; font-family: myriad-pro-1, myriad-pro-2, arial; padding: 0px; border: 0px initial initial;"> <li style="margin-top: 0px; margin-right: 0px; margin-bottom: 4px; margin-left: 0px; padding-left: 20px; vertical-align: baseline; border-image: initial; outline-width: 0px; outline-style: initial; outline-color: initial; background-image: url(http://amplifi.dlink.com/resource/1325889383000/LumSitesCSS/lumSitesCSS/images/LumSitesGlobalSprite.png); background-attachment: scroll; background-origin: initial; background-clip: initial; background-position: 0px -297px; background-repeat: no-repeat no-repeat; border: 0px initial initial;"> 最高300Mbpsの転送速度</li> <li style="margin-top: 0px; margin-right: 0px; margin-bottom: 4px; margin-left: 0px; padding-left: 20px; vertical-align: baseline; border-image: initial; outline-width: 0px; outline-style: initial; outline-color: initial; background-image: url(http://amplifi.dlink.com/resource/1325889383000/LumSitesCSS/lumSitesCSS/images/LumSitesGlobalSprite.png); background-attachment: scroll; background-origin: initial; background-clip: initial; background-position: 0px -297px; background-repeat: no-repeat no-repeat; border: 0px initial initial;"> HD Fuel&trade; QoS 搭載。高負荷のアプリケーションを自動識別して帯域を優先的割当</li> <li style="margin-top: 0px; margin-right: 0px; margin-bottom: 4px; margin-left: 0px; padding-left: 20px; vertical-align: baseline; border-image: initial; outline-width: 0px; outline-style: initial; outline-color: initial; background-image: url(http://amplifi.dlink.com/resource/1325889383000/LumSitesCSS/lumSitesCSS/images/LumSitesGlobalSprite.png); background-attachment: scroll; background-origin: initial; background-clip: initial; background-position: 0px -297px; background-repeat: no-repeat no-repeat; border: 0px initial initial;"> ギガビットイーサネット対応</li> <li style="margin-top: 0px; margin-right: 0px; margin-bottom: 4px; margin-left: 0px; padding-left: 20px; vertical-align: baseline; border-image: initial; outline-width: 0px; outline-style: initial; outline-color: initial; background-image: url(http://amplifi.dlink.com/resource/1325889383000/LumSitesCSS/lumSitesCSS/images/LumSitesGlobalSprite.png); background-attachment: scroll; background-origin: initial; background-clip: initial; background-position: 0px -297px; background-repeat: no-repeat no-repeat; border: 0px initial initial;"> SharePort&trade; Plus テクノロジーでUSB2.0デバイスを共有可能</li> </ul> <p> &nbsp;</p>