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;統計不重複字段有哪些
select * from table1 order by time limit 9,10 從第十條開始，輸出10條記錄 （起始點，長度）