MySQL索引查询（EXPLAIN UNION）

凯航仔2024-05-29 10:06

sql 复制代码

explain select * from city where ID>500 limit 10;

explain select `Name`,CountryCode,District from city where District='Utrecht';



explain select `Name`,CountryCode,District from city where ID=5;

explain select `Name`,CountryCode,District from city where ID<5;

explain select `Name`,CountryCode,District from city where CountryCode like 'NL_';

explain select `Name`,CountryCode,District from city where CountryCode='NLD' OR CountryCode='PHL';

explain select `Name`,CountryCode,District from city where CountryCode in('NLD','PHL');

explain select * from city where ID>500 limit 10；

explain select `Name`,CountryCode,District from city where District='Utrecht';

explain select `Name`,CountryCode,District from city where ID=5;

explain select `Name`,CountryCode,District from city where ID<5;

explain select `Name`,CountryCode,District from city where CountryCode like 'NL_';

explain select `Name`,CountryCode,District from city where CountryCode='NLD' OR CountryCode='PHL';

explain select `Name`,CountryCode,District from city where CountryCode in('NLD','PHL');

性能最快的方法是union联合查询

sql 复制代码

explain 
select `Name`,CountryCode,District from city where CountryCode='NLD'
union
select `Name`,CountryCode,District from city where CountryCode='PHL';