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 (199) 
  AND cscart_product_descriptions.lang_code = 'ja'

Query time 0.00050

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
199 <div class="wiki_section" style="margin-bottom: 15px; line-height: 18px; color: #3b3b3b; font-family: 'Gill Sans MT', tahoma, arial, sans-serif; font-size: 12px; text-align: left; background-color: #ffffff;"> 商品詳細<br /> <ul class="wiki_list"> <li class="wiki_listitem"> オーディオCD</li> <li class="wiki_listitem"> オリジナル版リリース日: 2005年9月13日</li> <li class="wiki_listitem"> 枚数: 2</li> <li class="wiki_listitem"> レーベル: ヴァージンレコードUS</li> </ul> </div> <div class="wiki_section" style="margin-bottom: 15px; line-height: 18px; color: #3b3b3b; font-family: 'Gill Sans MT', tahoma, arial, sans-serif; font-size: 12px; text-align: left; background-color: #ffffff;"> ディスク: 1 <ul class="wiki_list"> <li class="wiki_listitem"> 1. 3 O&#39;Clock Blues</li> <li class="wiki_listitem"> 2. Blind Love</li> <li class="wiki_listitem"> 3. She&#39;s Dynamite</li> <li class="wiki_listitem"> 4. You Know I Love You</li> <li class="wiki_listitem"> 5. Please Love Me</li> <li class="wiki_listitem"> 6. Story Fom My Heart And Soul</li> <li class="wiki_listitem"> 7. The Woman I Love</li> <li class="wiki_listitem"> 8. Neighborhood Affair</li> <li class="wiki_listitem"> 9. When My Heart Beats Like A Hammer</li> <li class="wiki_listitem"> 10. Every Day I Have The Blues</li> <li class="wiki_listitem"> 11. Love You Baby (Take A Swing With Me)</li> <li class="wiki_listitem"> 12. Ten Long Years</li> <li class="wiki_listitem"> 13. You Upset Me, Baby</li> <li class="wiki_listitem"> 14. Boogie Rock (House Rocker)</li> <li class="wiki_listitem"> 15. Crying Won&#39;t Help You</li> <li class="wiki_listitem"> 16. Bad Luck</li> <li class="wiki_listitem"> 17. Did You Ever Love A Woman</li> <li class="wiki_listitem"> 18. You Don&#39;t Know</li> <li class="wiki_listitem"> 19. Sweet Little Angel</li> <li class="wiki_listitem"> 20. On My Word Of Honor</li> </ul> <br /> ディスク: 2 <ul class="wiki_list"> <li class="wiki_listitem"> 1. Be Careful With A Fool</li> <li class="wiki_listitem"> 2. Please Accept My Love</li> <li class="wiki_listitem"> 3. Days Of Old</li> <li class="wiki_listitem"> 4. Worry, Worry</li> <li class="wiki_listitem"> 5. Confessin&#39; The Blues</li> <li class="wiki_listitem"> 6. Sweet Sixteen Parts 1 &amp; 2</li> <li class="wiki_listitem"> 7. Ain&#39;t Nobody&#39;s Business</li> <li class="wiki_listitem"> 8. Walkin&#39; Dr. Bill</li> <li class="wiki_listitem"> 9. My Own Fault</li> <li class="wiki_listitem"> 10. You Done Lost Your Good Thing Now</li> <li class="wiki_listitem"> 11. Downhearted (How Blue Can You Get?)</li> <li class="wiki_listitem"> 12. I&#39;ll Survive</li> <li class="wiki_listitem"> 13. Mashed Potato Twist</li> <li class="wiki_listitem"> 14. Down Now</li> <li class="wiki_listitem"> 15. Peace Of Mind</li> <li class="wiki_listitem"> 16. That Evil Child</li> <li class="wiki_listitem"> 17. Blues Stay Away From Me</li> <li class="wiki_listitem"> 18. Rock Me Baby</li> <li class="wiki_listitem"> 19. Miss Martha King</li> <li class="wiki_listitem"> 20. When Your Baby Packs Up And Goes</li> </ul> </div> <p> &nbsp;</p>