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数据库常用不使用索引情况

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Release： 2016-06-07 14:53:58
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数据库常用不使用索引情况 1.使用,!=,^= 不使用索引可以使用 in or 或重写 www.2cto.com 2.is null不使用索引避免方法是定义成非空或者有默认值 通过默认值检索 3.is not null 如果大多数值都是空 非常高效 4.使用函数将禁用索引 5.仅当like以%开头时使用btr


数据库常用不使用索引情况

 

1.使用,!=,^= 不使用索引可以使用 in or 或>重写 

  www.2cto.com  

2.is null不使用索引避免方法是定义成非空或者有默认值 通过默认值检索 

 

3.is not null 如果大多数值都是空 非常高效 

 

4.使用函数将禁用索引 

 

5.仅当like以%开头时使用btree索引

Related labels：
use Condition database Use or not index
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