数据库SQL

表名以 table_name 为例

增 用于向数据库表中插入新数据

    insert into table_name valuse ('ke','xiong','China','Wuhan') // 插入新的行
    insert into table_name values ('ke','xiong','China','Wuhan'),('xiong','jia','Chain','Chongqin')
    insert into table_name (LastName,FirstName) values ('xiong','mao') //插入指定的列

删 用于向数据库表中删除数据 * 条件不能漏写否则会删除所有的行

    delete from table_name where FirstName = 'xiong'
    delete LastName from table_name where FirstName = 'xiong'

改 用于修改数据库中表的数据 * 条件不能漏写否则会修改所有的行

    update table_name set LastName = 'yao' where FirstName = 'xiong'
    update table_name set LastName = 'yao',City = 'Chongqi' where FirstName = 'xiong'

查 用于查找数据库中表的数据

    select * from table_name
    select LastName,FirstName from table_name
    selct distinct from table_name // distinct 列出唯一的值
    select distinct FirstName from table_name
    select FirstName from table_name where City='Wuhan' and (Year>1998 or Lastname like '%e')
    select Age,OrderNmuber from table_name order by Age,OrderNmuber //年龄顺序显示年龄 以订单顺序显示订单名字
    select Age,OrderNmuber from table_name order by age desc // 以年龄倒序显示
     select Age,OrderNmuber from table_name order by age desc,orderNumber ASC//以倒序显示年龄、顺序显示订单号