MySQL——不同查询方式

不同查询方式

explain select * from city;

#主键查询
explain select * from city where ID=5;

#索引查询
explain select * from city where CountryCode='NLD';

#主键范围查询
explain select * from city where ID>5 and ID<20;

#非索引范围查询
explain select * from city where Population>193238 and Population<200000;

查询结果