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怎样高效遍历联合主键的表?
source link: https://www.v2ex.com/t/915882
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create table t
(
a int not null,
b varchar(128) not null,
primary key (b, a)
)
t 有千万行吧, 一般怎么样高效遍历这样的表呢?
只能select * from t where b = 'xx' and a > 'yy' limit 1000?
问题是 column b 区分度大的话, 每次取到的数据可能远小于 1000
上面用 mysql 的方式讨论一般思路, 其实这个 DB 是 SQL server(第一次用 SQL server), 有特殊技巧吗?
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