我有两个用于广告素材的表格及其缩略图。我想以类似的备用查询方式：
Initially, the thumbnail will be displayed for 300x250
IF not available then 336x280,
IF not available then 300x600,
IF not available then 728x90,
IF not available then 160x600,
IF not available then 320x50,
IF not available then 300x50,
IF not available then 468x60
表结构就像
creatives:
id INT
name VARCHAR
desc TEXT
creative_thumbs:
id
creative_id INT
dimension VARCHAR
img_url VARCHAR
我已经通过多个连接（每个维度一个连接，但是速度有点慢）实现了
答案 0 :(得分：0)
您可以使用多个<button id="MAINPART" class="accordion"> Main Part</button>
<div class="panel">
<p>
<div class="tab">
<button class="tablinks" onclick="openFunctionality(event, 'ONE')" id="defaultOpen"> ONE </button>
<button class="tablinks" onclick="openFunctionality(event, 'TWO')"> TWO </button>
<button class="tablinks" onclick="openFunctionality(event, 'Three')">Three</button>
</div>
<!--Configuration Tab-->
<div id="ONE" class="tabcontent">
<button class="accordion">1st- part</button>
<div class="panel">
<button class="accordion">1st- part1</button>
<button class="accordion">1st- part2</button>
<button class="accordion">1st- part3</button>
</div>
<button class="accordion" id="2nd">2nd part</button>
<button class="accordion" id="3rd">3rd part </button>
</div>
</p>
</div>
<button class="accordion"> secondery </button>
<div class="panel">2nd</div>
<button class="accordion"> others </button>
<div class="panel">3rd</div>查询来执行此操作。应该是这样的：
LEFT JOIN如果这太慢，则尝试将索引添加到SELECT
c.Name AS CreativeName,
COALESCE(
ct1.Dimension,
ct2.Dimension,
ct3.Dimension,
ct4.Dimension,
ct5.Dimension,
ct6.Dimension,
ct7.Dimension,
ct8.Dimension
) AS ThumbnailDimension
FROM creatives c
LEFT JOIN creative_thumbs ct1 ON c.id = ct1.creative_id AND ct1.Dimension = '300x250'
LEFT JOIN creative_thumbs ct2 ON c.id = ct2.creative_id AND ct2.Dimension = '336x280'
LEFT JOIN creative_thumbs ct3 ON c.id = ct3.creative_id AND ct3.Dimension = '300x600'
LEFT JOIN creative_thumbs ct4 ON c.id = ct4.creative_id AND ct4.Dimension = '728x90'
LEFT JOIN creative_thumbs ct5 ON c.id = ct5.creative_id AND ct5.Dimension = '160x600'
LEFT JOIN creative_thumbs ct6 ON c.id = ct6.creative_id AND ct6.Dimension = '320x50'
LEFT JOIN creative_thumbs ct7 ON c.id = ct7.creative_id AND ct7.Dimension = '300x50'
LEFT JOIN creative_thumbs ct8 ON c.id = ct8.creative_id AND ct8.Dimension = '468x60'
;
列：
Dimension