4
439SELECT help_category_id,`name`,parent_category_id,`url`
FROM `help_category`
WHERE help_category_id!=5
VS
SELECT help_category_id,`name`,parent_category_id,`url`
FROM `help_category`
WHERE help_category_id<=4 OR help_category_id>=6
附 !=5也能用上索引
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个人认为，如果help_category_id字段有索引
<4 >6这种方式是可以利用上索引的，但是!=5是用不了索引的亲，help_category_id<4 AND help_category_id>6可以直接被解析为False，当然快了。题主已改问题，忽略我吧。
SELECT help_category_id,name,parent_category_id,url FROM help_category WHERE help_category_id between 4 and 6 and help_category_id!=5