如何使用sql語句

這篇文章給大家分享的是有關(guān)如何使用sql語句的內(nèi)容。小編覺得挺實(shí)用的，因此分享給大家做個(gè)參考，一起跟隨小編過來看看吧。

update

1、set一個(gè)字段在表t_test中設(shè)置第二條記錄（bs為2）的password為'***'。update t_test t    set t.password = '***' where t.bs = 2;

http://lavasoft.blog.51cto.com/62575/27692

login

mysql -h 11.11.11.1 -u root -p

mysql -u root -p

view table field 

desc tablename

mysql> select host,user from mysql.user;
+-----------+-------------+
| host      | user        |
+-----------+-------------+
| %         | fishadmin   |
| %         | jiraadmin   |
| %         | root        |
| %         | udanceadmin |
| localhost | fishadmin   |
| localhost | jiraadmin   |
| localhost | jirauser    |
| localhost | root        |
+-----------+-------------+
8 rows in set (0.00 sec)

%意思任意主機(jī)都可以連接

android Sqlite

--update message set readstatus = 1 where sender = 13455556669 and receiver = 13455556667 and readstatus = 0;

--select * from message where readstatus <> 0;//readstatus不等于0的數(shù)據(jù)

--select * from message where sender='13455556661' and receiver='13455556663' and process=103 order by _id desc;
--select * from message limit 3;--只查詢前三條數(shù)據(jù)
--select * from message limit 2,1;--指定偏移量和查詢數(shù)據(jù)條數(shù)
select count(1) from message;--查詢消息表中的數(shù)據(jù)條數(shù)

2.數(shù)據(jù)庫查詢語句
select * from message order by _id asc;按_id的升序
select * from message order by _id desc;按_id的降序
2.1
select sender,receiver,content from message group by sender order by _id desc;
當(dāng)order by和group by一起使用的時(shí)候，要先用group by，再用order by

4.關(guān)于刪除
從message表中刪除_id=2的一條記錄的SQL語句：
delete from message where _id = '2';
參考：http://blog.sina.com.cn/s/blog_69092aea0101879o.html
--select * from message order by _id desc;
--select * from message where sender = 'hello1' and receiver = 'hello2' or sender = 'hello2' and receiver = 'hello1';
--select * from message where sender = 'hello2' and receiver = 'hello1';
--CREATE TABLE IF NOT EXISTS temporder(_id INTEGER PRIMARY KEY AUTOINCREMENT, ordernumber text, ordertime text, appointtime text, appointstatus text, stationname text, serviceitem text,saname text, telephone text, rating text, commentcount text, isAuth INTEGER,
carbrand text, carkind text, carnum text, carage text, carmiles text, worktime text, price text, shoplongi text, shoplati text);
--CREATE TABLE IF NOT EXISTS ordera (_id INTEGER PRIMARY KEY AUTOINCREMENT, ok text);
--select _id, appointstatus, appointtime, ordernumber, stationname, serviceitem, saname, telephone from repairorder where telephone=13566667777;

--delete from message where _id = '2';

--CREATE TABLE IF NOT EXISTS carinfo (_id INTEGER PRIMARY KEY AUTOINCREMENT, carLogo INTEGER, carNum TEXT, carBrand TEXT, carLevel TEXT, carYear TEXT, phone TEXT);
--delete from message;
--select content from message where _id < 50 order by _id asc;
--select * from message group by sender;-- where readstatus = 0
--select * from message where receiver = 13455557777;
--update message set readstatus = 0 ;--where sender = 13455556667 and receiver = 13455557777;
--select * from message where readstatus=1 group by sender;
--delete from friendrequest;
--update friendrequest set agree=10 where reqfrom='13455556664' and reqto='13455556665';
--update friendrequest set agree = 13,icon='abc',added=32 where reqfrom= '13455556664' and reqto= '13455556665';
--select content from message;
--select _id from carinfo;
--update carinfo set carid = 110 where _id=12;
--delete from message;
--create table friends (username TEXT);
delete from friends where username = '13455556668' and jid='13455557777@iz280uotbvjz';??

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