show databases;
show tables;
show variables like "%max_connections%"
select * from table1
select count(*) from table1
select * from table1 order by time DESC limit 100
select distinct name from table1;统计不重复字段有哪些
select * from table1 order by time limit 9,10 从第十条开始，输出10条记录 （起始点，长度）
