# 总查询
EXPLAIN SELECT * FROM `city`;# 范围查询
EXPLAIN SELECT * from `city` where ID>5 and ID<20;
#主键查询
EXPLAIN SELECT * from `city` where ID=5;
# 索引查询
EXPLAIN SELECT * from `city` where CountryCode='NLD';
# 普通索引
EXPLAIn SELECT * from `city` where Name='haag';
EXPLAIN SELECT * from `city` where CountryCode in ('NLD','DZA');
)
